Publications by authors named "Sepehr Hamidi"

Traditional histochemical staining of post-mortem samples often confronts inferior staining quality due to autolysis caused by delayed fixation of cadaver tissue, and such chemical staining procedures covering large tissue areas demand substantial labor, cost and time. Here, we demonstrate virtual staining of autopsy tissue using a trained neural network to rapidly transform autofluorescence images of label-free autopsy tissue sections into brightfield equivalent images, matching hematoxylin and eosin (H&E) stained versions of the same samples. The trained model can effectively accentuate nuclear, cytoplasmic and extracellular features in new autopsy tissue samples that experienced severe autolysis, such as COVID-19 samples never seen before, where the traditional histochemical staining fails to provide consistent staining quality.

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While apoptosis plays a significant role in intestinal homeostasis, it can also be pathogenic if overactive during recovery from inflammation. We recently reported that microRNA-24-3p (miR-24-3p) is elevated in the colonic epithelium of ulcerative colitis patients during active inflammation, and that it reduced apoptosis in vitro. However, its function during intestinal restitution following inflammation had not been examined.

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Development of post-chemotherapy histiocyte-rich pseudotumor (PHP) is an underrecognized event following therapy in lymphoma patients and may mimic residual tumor using current therapy monitoring protocols. We report a series of 5 patients with PHP along with a review of the literature. In our series, we describe 3 patients with persistent hypermetabolic masses by positron emission tomography-computed tomography, one with persistent terminal ileal nodules on endoscopy, and one with bone marrow involvement, a site not associated with mass-like disease.

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Anetoderma is a rare cutaneous disorder presenting with atrophic skin lesions. It can be associated with several autoimmune and infectious diseases. With the current resurgence of syphilis, clinicians must be aware of its association with anetoderma.

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Background: Interleukin-6 blockade (IL-6) has become a focus of therapeutic investigation for the coronavirus disease 2019 (COVID-19).

Methods: We report a case of a 34-year-old with COVID-19 pneumonia receiving an IL-6 receptor antagonist (IL-6Ra) who developed spontaneous colonic perforation. This perforation occurred despite a benign abdominal exam and in the absence of other known risk factors associated with colonic perforation.

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Neutrophilic figurate erythema of infancy (NFEI) is a rare variant of annular erythema of infancy. It is characterized by annular erythematous plaques, occasionally with a polycyclic configuration. The main challenge is to differentiate this rare entity from other figurate erythemas associated with serious diseases such as neonatal lupus erythematosus.

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Hydrophilic polymer coatings were designed to reduce friction between the catheter and vessel wall and facilitate intravascular manipulations during catheterization and placement of drug-eluting stents. One newly reported complication of such hydrophilic coatings is the fragmentation and embolization of the polymer, which can lead to ischemia and infarct by blocking the small vasculature. In this report, we present a patient with a non-healing ulcer on the leg.

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Background: Previously, we studied the genetic basis for variability in total thyroxine (TT4) as part of investigating induced Graves' hyperthyroidism in panels of genetically diverse recombinant inbred (RI) mice. Because Graves' disease occurs predominantly in women, we used female mice. A limitation of this approach is that thyrotropin (TSH) is undetectable by some assays in most female mice.

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Despite elucidation of the crystal structure of M22, a human thyroid-stimulating autoantibody (TSAb) bound to the TSH receptor (TSHR) leucine-rich repeat domain (LRD), the mechanism by which TSAs activate the TSHR and cause Graves' disease remains unknown. A nonstimulatory murine monoclonal antibody, 3BD10, and TSAb interact with the LRD N-terminal cysteine cluster and reciprocally distinguish between two different LRD conformational forms. To study this remarkable phenomenon, we investigated properties of 3BD10, which has a linear epitopic component.

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Background: Graves' hyperthyroidism is induced by immunizing mice with adenovirus expressing the human thyrotropin (TSH)-receptor. Using families of recombinant-inbred mice, we previously discovered that genetic susceptibility to induced thyroid-stimulating antibodies and hyperthyroidism are linked to loci on different chromosomes, indicating a fundamental genetic difference in thyroid sensitivity to ligand stimulation. An approach to assess thyroid sensitivity involves challenging genetically diverse lines of mice with TSH and measuring the genotype/strain-specific increase in serum thyroxine (T4).

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Background: Thyroid-stimulating autoantibodies (TSAb) bind to the thyrotropin receptor (TSHR) extracellular domain, or ectodomain (ECD), comprising a leucine-rich repeat domain (LRD) linked by a hinge region to the transmembrane domain (TMD). The LRD (residues 22-260; signal peptide 1-21) contains two disulfide-bonded loops at its N-terminus. In the crystal structure of the isolated LRD complexed with human TSAb monoclonal antibody (mAb) M22, N-terminal disulfide loop 1 (residues 22-30) could not be determined because of crystal disorder.

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The glycoprotein hormone receptor hinge region is the least conserved component and the most variable in size; the TSH receptor (TSHR) being the longest (152 amino acids; residues 261-412). The TSHR is also unique among the glycoprotein hormone receptor in undergoing in vivo intramolecular cleavage into disulfide-linked A- and B-subunits with removal of an intervening 'C-peptide' region. Experimentally, hinge region amino acids 317-366 (50 residues) can be deleted without alteration in receptor function.

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Background: Recombinant-inbred mouse strains differ in their susceptibility to Graves'-like hyperthyroidism induced by immunization with adenovirus expressing the human thyrotropin (TSH) receptor. Because one genetic component contributing to this susceptibility is altered thyroid sensitivity to TSH receptor agonist stimulation, we wished to quantify thyroid responsiveness to TSH. For such studies, it is necessary to suppress endogenous TSH by administering L-3,5,3′-triiodothyronine (L-T3), with the subsequent decrease in serum thyroxine (T4) reflecting endogenous TSH suppression.

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Hashimoto's thyroiditis, a common autoimmune disease, is associated with autoantibodies to thyroglobulin (Tg) and thyroid peroxidase (TPO). TPO, unlike abundant and easily purified Tg, is rarely investigated as an autoantigen in animals. We asked whether antibodies (Abs) develop to both TPO and Tg in thyroiditis that is induced (C57BL/6 and DBA/1 mice) or arises spontaneously (NOD.

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Aims: To investigate the effects of spironolactone on serum lipids in women with hirsutism over a 3-month period.

Methods: In a prospective setting, 27 hirsute women (20 with polycystic ovary syndrome and seven with idiopathic hirsutism) with a mean age of 23.0 +/- 5.

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Objective: To study the prevalence and correlates of increased urinary albumin excretion (UAE) in an Iranian type 2 diabetic population.

Methods: Over a one year period since October 2002, 400 consecutive type 2 diabetic patients referred to an outpatient diabetes clinic, were enrolled in a cross sectional study. Subjects had no history of renal impairment or overt proteinuria.

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Objective: To determine the association of thyroglobulin antibodies (TG-Ab) and thyroid peroxidase antibodies (TPO-Ab) with recurrent spontaneous abortion in a euthyroid, nonpregnant population of women in Iran.

Methods: In this case-control study conducted between November 2003 and September 2006 in Tehran, Iran, nonpregnant women with a history of 3 or more consecutive pregnancy losses and age-matched, healthy parous women without a history of reproductive problems were assessed. Thyroid function tests were performed, which included assessment of thyroid-stimulating hormone, triiodothyronine, thyroxine, and the presence of TG-Ab and TPO-Ab.

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Objective: To determine the distribution of solitary parathyroid adenoma over the parathyroid glands in a group of patients with primary hyperparathyroidism Design: A case-series.

Place And Duration Of Study: Departments of Surgery and Pathology at Shariati Hospital, Tehran, Iran, between the years 1981 and 2003.

Patients And Methods: A retrospective review of surgery reports of 118 patients with primary hyperparathyroidism was performed.

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Background: Preoperative laboratory findings may carry some predictive value about the size of the abnormal parathyroid tissue that needs to be removed in primary hyperparathyroidism.

Methods: In a retrospective study from 1988 to 2003, records of 71 patients with parathyroid adenoma were reviewed. The correlation between preoperative serum calcium, phosphate and parathyroid hormone (PTH) with adenoma's weight was analysed separately.

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