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Biomedical subjects

H A Hassan

Publications and source records attributed to H A Hassan.

At least 19 recordsLinked to original sources
PubMed2001

Biological activities of two porcine growth hormone-releasing hormone receptor isoforms.

Binding of growth hormone-releasing hormone (GHRH) to two isoforms (G3R and G5R) of the porcine GHRH receptor was studied. Both G3R- and G5R-cDNA were isolated from a porcine anterior pituitary cDNA library and have an identical primary structure from aa 1 to 418 and a different aa sequence from aa 419 to 423. In addition, the G5R isoform contains an extra C-terminal tail of 28 aa. The G3R and G5R mRNAs arise from alternative splicing of a single precursor mRNA for GHRH receptors. A mammalian cell expression vector containing either G3R or G5R cDNA under the regulation of a strong human cytomegalovirus promoter was constructed and used to transfect a human embryonic kidney 293 cell line. Two stable transfectants (293/G3R-4 and 293/G5R-12) were isolated on the basis of high expression of the receptor mRNAs. Both G3R and G5R mRNAs were expressed at similarly high levels in 293/G3R-4 and 293/G5R-12 cells; however, GHRH binding to 293/G3R-4 cells was much greater than that observed for 293/G5R-12 cells. Basal as well as GHRH-stimulated GTPase activity and intracellular cAMP concentration are also significantly greater in 293/G3R-4 cells as compared to 293/G5R-12 cells. We conclude that the modification of GHRH receptor at the C-terminal region hindered GHRH binding to the receptor and thus attenuates its biological activities.

Amino Acid Sequence↗
PubMed2001

Effect of treatment with Ginkgo biloba extract EGb 761 (oral) on unilateral idiopathic sudden hearing loss in a prospective randomized double-blind study of 106 outpatients.

OBJECTIVE: Test of dose-response relationship for Ginkgo biloba extract EGb 761 (oral) in outpatients with acute idiopathic sudden sensorineural hearing loss (ISSHL) of at least 15 dB at one frequency within the speech range occurring less than 10 days before study inclusion. DESIGN: Multicentre, randomized, double-blind phase III study comparing dosages of 120 mg twice daily and 12 mg twice daily over 8 weeks. MAIN ENDPOINT: Recovery (in dB) of the auditory threshold from the initial measurement to the value on the last day of treatment, averaged over those frequencies from 0.25, 0.5, 1, 2, and 3 kHz for which the initial hearing loss amounted to 15 dB or more compared to the level on the opposite side. PATIENTS: 106 patients with an average age of 44+/-16 years and with hearing loss at affected frequencies 26 dB +/- 9 dB included between December 1995 and July 1997. RESULTS: Large majorities of both treatment groups recovered completely. In exploratory analyses of the 96 patients included according to the protocol, patients given the higher dose had less risk of not recovering well (< or =10 dB residual hearing loss) (one-sided Fisher test: P = 0.0061), especially if they had no tinnitus (n = 44, P = 0.00702). CONCLUSION: A higher dosage of EGb 761 (oral) appears to speed up and secure the recovery of ISSHL patients, with a good chance that they will recover completely, even with little treatment. This was already observed after one week of treatment. We find it justified to treat patients who have unilateral ISSHL of less than 75 dB and neither tinnitus nor vertigo with 120 mg oral EGb 761 twice daily.

Acute Disease↗
PubMed2001

Pregnene derivatives from Solenostemma argel leaves.

Two new pregnene derivatives 14beta-15alpha-dihydroxy-delta4pregnene-3,20 dione and 3beta-14beta,15alpha-16alpha hydroxy-20-oxo-delta5pregnene-tetra-ol, in addition to alpha- and beta-amyrin and beta-sitosterol, were isolated from Solenostemma argel leaves. The structures were established by extensive spectral analysis as well as comparison with reference materials.

Africa, Northern↗
PubMed2001

Estrogen and androgen elicit growth hormone release via dissimilar patterns of hypothalamic neuropeptide secretion.

The dimorphic pattern of growth hormone (GH) secretion and somatic growth in male and female mammals is attributable to the gonadal steroids. Whether these hormones mediate their effects solely on hypothalamic neurons, on somatotropes or on both to evoke the gender-specific GH secretory patterns has not been fully elucidated. The purpose of this study was to determine the effects of 17beta-estradiol, testosterone and its metabolites on release of GH, GH-releasing hormone (GHRH) and somatostatin (SRIF) from bovine anterior pituitary cells and hypothalamic slices in an in vitro perifusion system. Physiological concentrations of testosterone and estradiol perifused directly to anterior pituitary cells did not affect GH releases; whereas, dihydrotestosterone and 5alpha-androstane-3alpha, 17beta-diol increased GH. Perifusion of testosterone at a pulsatile rate, and its metabolites and estradiol at a constant rate to hypothalamic slices in series with anterior pituitary cells increased GH release. The androgenic hormones increased GHRH and SRIF release from hypothalamus; whereas, estradiol increased GHRH but decreased SRIF release. Our data show that estradiol and the androgens generated distinctly different patterns of GHRH and SRIF release, which in turn established gender-specific GH patterns.

Androgens↗
PubMed2001

Cumulus cell contribution to cytoplasmic maturation and oocyte developmental competence in vitro.

OBJECTIVE: Although several reports indicated the bidirectional communication between the oocyte and granulosa cell, and the potential negative impact of premature cumulus removal, clinical data are controversial. The present analysis report the results of a prospective randomized study done on sibling oocytes to evaluate whether or not preincubation with intact cumulus is needed in ICSI. METHODS: It was a prospective randomized study, and conducted at Alexandria IVF-ICSI center. This study was performed using 926 M2 oocytes from 141 cycles of patients undergoing ICSI. Oocytes were randomized between three protocols: protocol A (immediate denudation, immediate injection), protocol B (delayed denudation, delayed injection), and protocol C (early denudation, delayed injection). Main outcome measure(s) were maturation, fertilization, and cleavage rate after ICSI. RESULTS: Aspects of nuclear, cytoplasmic maturation and oolemma properties were improved when oocytes were preincubated with intact cumulus before ICSI. CONCLUSIONS: Preincubation, before ICSI improved results. Duration of preincubation should be program specific.

Female↗
PubMed2001

Effects of growth hormone on in vitro maturation of germinal vesicle of human oocytes retrieved from small antral follicles.

PURPOSE: Evaluation of the effect of GH, administered in vivo, on in vitro maturation of human GV oocytes obtained from small follicles. METHODS: The study included 88 ICSI women stimulated with long agonist protocol. They were randomly allocated to two groups (Group 1, 44 women with 86 GV oocytes), were cotreated with GH (Group 2, no GH: 44 women with 67 GV oocytes). GV oocytes from small follicles were matured in vitro, injected, and their development observed. RESULTS: Resumption of meiosis was significantly higher in Group 1 compared to Group 2 (60 and 37.3% respectively). Significantly more M2 oocytes were obtained in Group 1 than in Group 2 (45.5 and 23.9% respectively). Fertilization rates were also significantly higher (51.9 and 18.8% respectively). No embryos were obtained in Group 2, whereas 21.1% of fertilized oocytes in Group 1 cleaved into class A embryos. CONCLUSION: In vivo administration of GH enhanced in vitro maturation and fertilization of human GV oocytes retrieved from small antral follicles.

Adult↗
PubMed2001

Changing trends in gastric carcinoma at a university medical center: a twelve-year retrospective analysis.

Over the past 60 years, the epidemiology of gastric adenocarcinoma has changed considerably. The most striking change in the epidemiology of gastric adenocarcinoma has been the rapid increase in cancers of the proximal stomach. We performed a retrospective analysis of all gastric adenocarcinomas diagnosed at two hospitals in Little Rock, Arkansas, U.S.A., between 1985 and 1996. Two hundred seventeen patients were diagnosed with gastric adenocarcinoma. Patients were divided into three 4-year cohorts. We found that the proportions of gastric cardia adenocarcinoma in cohorts 1, 2, and 3 were 31%, 36%, and 42%, respectively (p = 0.52). Median survival in the three cohorts was 5, 8, and 8 months, respectively (p = 0.22). Median survival (stages 1-4) was 41.5, 11.5, 10, and 3 months, respectively (p < 0.0001). Well-, moderately-, and poorly- differentiated adenocarcinoma had median survivals of 18, 7.5, and 6 months, respectively (p = 0.07). We concluded that patients with gastric adenocarcinoma continue to be diagnosed at late stages. There has been a trend toward an increasing proportion of cardia adenocarcinoma. Stage at presentation was the only significant predictor of survival.

Adenocarcinoma↗
PubMed2000

Diagnosis and staging of head and neck cancer: a comparison of modern imaging modalities (positron emission tomography, computed tomography, color-coded duplex sonography) with panendoscopic and histopathologic findings.

OBJECTIVE: To compare the clinical value of positron emission tomography (PET) using fludeoxyglucose F 18, computed tomography (CT), color-coded duplex sonography (CCDS), and panendoscopy in the detection and staging of head and neck cancer. DESIGN: Prospective nonrandomized controlled study. SETTING: Medical school. PATIENTS: Convenience sample of 50 patients with suspected primary or recurrent head and neck cancer. INTERVENTION: Biopsy, tumor surgery. MAIN OUTCOME MEASURES: Information of diagnostic procedures compared with histopathologic features. RESULTS: Both PET and panendoscopy had a sensitivity of 95% and 100% for detection of primary tumor or recurrent carcinomas, respectively. Specificity for PET and panendoscopy was 92% and 85% in primary tumors and 100% and 80% in recurrent carcinoma, respectively. Sensitivity of CCDS and CT was 74% and 68% in primary tumors and 67% and 63% in recurrent carcinomas, respectively. Specificity was 75% and 69% in primary tumors and 100% and 80% in recurrent neoplasms. When assessing neck nodes, all imaging procedures exhibited identical sensitivity (84%). Specificity was 90%, 96%, and 88% in PET, CT, and CCDS, respectively. In recurrent lymph node metastases, sensitivity was 100%, 67%, and 67% and specificity was 87%, 91%, and 87% for PET, CT, and CCDS, respectively. CONCLUSIONS: Positron emission tomography was the most reliable imaging procedure in the detection of primary tumor and recurrent carcinomas localized in the head and neck region. Owing to its limited anatomical depiction, it cannot as yet replace other diagnostic procedures in preoperative planning but does contribute valuable complementary diagnostic information. Computed tomograpy may have difficulties in identifying recurrent carcinomas. For routine diagnosis of nodal spread in the neck, CCDS is recommended. Panendoscopy is a valuable diagnostic procedure that can provide key information in cases of superficial mucosal tumor involvement. Arch Otolaryngol Head Neck Surg. 2000;126:1457-1461

Biopsy↗
PubMed2000

Degradation of the Photosystem II D1 and D2 proteins in different strains of the cyanobacterium Synechocytis PCC 6803 varying with respect to the type and level of psbA transcript.

The turnover of the D1 and D2 proteins of Photosystem II (PSII) has been investigated by pulse-chase radiolabeling in several strains of the cyanobacterium Synechocystis PCC 6803 containing different types and levels of the psbA transcript. Strains lacking psbA1 and psbA3 gene and containing high levels of the psbA2 transcript showed the selective synthesis of D1 whose degradation could be slowed down by the protein synthesis inhibitor lincomycin. In contrast, in strains containing just the psbA3 gene, the intensity of the D1 protein labeling was lower and labeling of the D2 and CP43 proteins was stimulated in comparison to the psbA2-containing strains. In addition, the rate and selectivity of the D1 degradation and its dependence on the presence of lincomycin was proportional to the level of the psbA3 transcript in the particular strain. Consequently, there was parallel, lincomycin-independent and slowed-down breakdown of the D1 and D2 proteins in strains with the lowest level of psbA3 transcript. These results are discussed in terms of a model in which the rate of D1 and D2 degradation in cyanobacteria is affected not only by the rate of PSII photodamage, but also by the availability of newly synthesized D1 protein. Moreover, the comparison of the non-oxygen-evolving D1 mutants D170A** and Y161F*** differing by the presence of tyrosine Z has indicated a minor role of the oxidized form of this secondary PSII electron donor in the donor side mechanism of D1 and D2 protein breakdown.

Algal Proteins↗
PubMed2000

[Multiple primary carcinomas in patients with head and neck malignancies].

BACKGROUND: Multiple primary tumors can lead to diagnostic and therapeutical problems. In this study we surveyed frequency, localisation, diagnostic, chronologic and therapeutic aspects of multiple primary carcinomas in patients with head and neck tumors. PATIENTS AND METHODS: The data of 843 patients from the tumor registry of the ENT-clinic Aachen were retrospectively studied. RESULTS: Larynx (41.87%) and oropharynx (12.57%) were the main localisation of the first primary neoplasma. In 65 patients (7.71%) multiple primary tumors were observed. 24.6% of these tumors occurred synchronously. Preferential localisation of a second tumor were lung (20%), oral cavity (15.3%) and larynx (13.8%). 28.57% of the metachronous tumors were observed after more than five years. In 46.15% clinical complaints led to the suspicion of a second tumor. Panendoscopy was the most reliable diagnostic procedure. The survival rate and time was significantly reduced in patients with synchronous tumors. 3-year survival rate was 15% compared to 81% in patients with metachronous tumor appearance (p < 0.0001). CONCLUSION: Patients with head and neck tumors have a high incidence of multiple primary malignomas varying from the region of the first presentation of a malignant tumor. Concepts comprising surgery provide the highest survival rates. Because of the high incidence of metachronous carcinomas after five years found in this study, the authors regard a prolonged follow-up period as necessary.

Combined Modality Therapy↗
PubMed2000

Zinc-induced copper deficiency in a coin swallower.

In humans, acquired copper deficiency anemia is rare. This report describes a 58-yr-old man with metal pica, especially coins, who presented with symptomatic anemia. His workup led to the diagnosis of zinc-induced copper deficiency. We believe that, in this man, leaching of zinc from pennies explained the clinical and laboratory findings. This case demonstrates that health care workers should consider the possibility of zinc-induced copper deficiency when confronted with patients with unexplained anemia who have ingested coins or other zinc-containing metals.

Bezoars↗
PubMed1999

Mesenteric venous thrombosis.

BACKGROUND: Mesenteric venous thrombosis is an uncommon but often lethal form of intestinal ischemia. METHODS: We reviewed pertinent literature on mesenteric venous thrombosis using MEDLINE search. RESULTS: We found that previous abdominal surgery and hypercoagulable states are the most common conditions associated with mesenteric venous thrombosis. The symptoms and signs related to mesenteric venous thrombosis are not specific. In the majority of cases, the diagnosis is established by a high index of clinical suspicion and noninvasive imaging techniques. Immediate operation is indicated if signs of peritonitis or intestinal infarction are present. Administration of heparin is beneficial for reducing recurrence and mortality. CONCLUSION: Clinicians should consider the possibility of acute mesenteric venous thrombosis when faced with a patient having abdominal pain out of proportion to the physical findings and with a negative workup for the common causes of abdominal pain.

Humans↗
PubMed1998

Double oocyte aspiration may be a solution for empty follicle syndrome: case report.

OBJECTIVE: To assess the possibility of salvaging the cycle in a case of empty follicle syndrome by scheduling a second retrieval. SETTING: Miami IVF/Intracytoplasmic Sperm Injection Center, Alexandria, Egypt. It is a private center. PATIENT(S): A 24-year-old female with a 6-year history of primary infertility. Intracytoplasmic sperm injection was performed because of her partner's obstructive azoospermia. No oocytes could be retrieved despite normal ultrasonic and hormonal responses and the presence of 25 mature follicles. INTERVENTION(S): Serum hCG on the day of the first retrieval. A second dose of hCG was given after the first retrieval, and a second retrieval was scheduled 24 hours later. MAIN OUTCOME MEASURE(S): Number of oocytes retrieved, fertilization and cleavage rates, and pregnancy outcome. RESULT(S): Serum beta-hCG level on the day of the first retrieval was 300 IU/mL. Eleven oocytes were retrieved, (7 were metaphase II, 3 fertilized, and 2 cleaved) and two embryos were transferred. No pregnancy resulted. CONCLUSION(S): In a variant of empty follicle syndrome, the cycle could be salvaged by giving another dose of hCG and scheduling another retrieval 24 hours later.

Adult↗
PubMed1997

Oral or vaginal misoprostol for induction of labor.

OBJECTIVE: To compare vaginal versus oral misoprostol for induction of labor. METHOD: Induction of labor was carried out in 40 women near term in two equal and randomized groups (according to a computer generated table) using misoprostol. Group I received vaginal misoprostol (100 micrograms) every 3 h while group II patients were given the same dose via the oral route. The dose was doubled if no response was detected under continuous cardiotocographic (CTG) tracings. RESULT: The vaginal route of administration induced a higher success rate in a shorter time interval using a lower dose but was associated with more abnormal FHR patterns and instances of uterine hyperstimulation. CONCLUSION: It is recommended to use the vaginal approach with cardiotocographic monitoring.

Administration, Intravaginal↗
PubMed1996

Endometrial unresponsiveness: a novel approach to assessment and prognosis in in vitro fertilization cycles.

OBJECTIVE: To categorize endometrial responsiveness to orally administered estriol in natural cycles of patients with thin endometrium. The value of endometrial responsiveness in predicting the outcome of subsequent IVF-ET cycles was evaluated. DESIGN: Prospective clinical study. SETTING: Miami IVF-ICSI Center, Alexandria, Egypt, a private center. PATIENTS: Forty-two patients undergoing IVF-ET. All had endometrial thickness < or = 7 mm at the time of maximal follicular diameter in natural cycle. INTERVENTION: Estriol was orally administered in subsequent unstimulated cycle. Patients were categorized into responsive and unresponsive groups (those with improved and unimproved endometrial thickness, respectively). Lastly, controlled ovarian hyperstimulation (COH) with or without estriol was started in the IVF-ET cycles. MAIN OUTCOME MEASURES: The endometrial thickness during COH with or without estriol, fertilization, pregnancy, and abortion rates. RESULTS: The responsive group compared with the unresponsive group had a significantly higher rate of improved endometrial thickness, a similar number of oocytes retrieved, a similar fertilization rate, and a significantly higher pregnancy rate. CONCLUSION: Patients with endometrial unresponsiveness to estriol in their natural cycles rarely improve by COH and have a poor pregnancy rate in IVF cycles.

Adult↗