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Biomedical subjects

J Werber

Publications and source records attributed to J Werber.

9 recordsLinked to original sources
PubMed1999

The calcium/calmodulin-dependent phosphodiesterase PDE1C down-regulates glucose-induced insulin secretion.

To understand the role cAMP phosphodiesterases (PDEs) play in the regulation of insulin secretion, we analyzed cyclic nucleotide PDEs of a pancreatic beta-cell line and used family and isozyme-specific PDE inhibitors to identify the PDEs that counteract glucose-stimulated insulin secretion. We demonstrate the presence of soluble PDE1C, PDE4A and 4D, a cGMP-specific PDE, and of particulate PDE3, activities in betaTC3 insulinoma cells. Selective inhibition of PDE1C, but not of PDE4, augmented glucose-stimulated insulin secretion in a dose-dependent fashion thus demonstrating that PDE1C is the major PDE counteracting glucose-dependent insulin secretion from betaTC3 cells. In pancreatic islets, inhibition of both PDE1C and PDE3 augmented glucose-dependent insulin secretion. The PDE1C of betaTC3 cells is a novel isozyme possessing a K(m) of 0.47 microM for cAMP and 0.25 microM for cGMP. The PDE1C isozyme of betaTC3 cells is sensitive to 8-methoxymethyl isobutylmethylxanthine and zaprinast (IC(50) = 7.5 and 4.5 microM, respectively) and resistant to vinpocetine (IC(50) > 100 microM). Increased responsiveness of PDE1C activity to calcium/calmodulin is evident upon exposure of cells to glucose. Enhanced cAMP degradation by PDE1C, due to increases in its responsiveness to calcium/calmodulin and in intracellular calcium, constitutes a glucose-dependent feedback mechanism for the control of insulin secretion.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1996

Reduced connexin 43 expression in high grade, human prostatic adenocarcinoma cells.

Gap junction-mediated communication is required for normal cellular growth and differentiation. As cancer is thought to be a manifestation of the breakdown of cell-cell communication, with the concomitant loss of growth control, it would be expected that alterations in the primary structure, processing, oligomerization or trafficking of connexin (cxn) molecules would have a profound effect on the neoplastic process. Here we a present a preliminary immunohistochemical and molecular analysis of cxn 43 expression in prostatic epithelial cells from resected human tissue. Our data indicate that benign prostatic epithelial cells express cxn 43 protein, but that this expression is diminished in more advanced, anaplastic cancer cells. These data suggest that decreased connexin expression is not involved in the initiation of prostate cancer, but rather occurs during the progression of the disease.

Adenocarcinoma↗
PubMed1983

Cervical pregnancy diagnosed by ultrasound.

The preoperative diagnosis of cervical pregnancy by ultrasound is described. To the authors' knowledge, this is the third such diagnosis that has been reported in the literature. Ultrasound examination showed a gestational sac with smooth margins occupying the entire cervix in a 23-year-old woman. It is suggested that this diagnosis be considered in the appropriate clinical setting of painless first trimester vaginal bleeding in a patient who has had an abortion or other gynecologic surgery.

Adult↗
PubMed1983

Unilateral absence of a pulmonary artery.

Congenital absence of a main pulmonary artery is a rare anomaly. Most patients without associated congenital cardiac abnormalities are asymptomatic, and the diagnosis is first suggested by the appearance of the involved lung on a routine chest roentgenogram. The ipsilateral lung will be smaller than normal, and the contralateral lung will be overinflated and may herniate across the midline. We describe eight children with unilateral pulmonary arterial atresia (seven on the right side, four of whom were without associated cardiac anomalies).

Adolescent↗
PubMed1983

The effect of thyroid hormone administration upon survival in patients with differentiated thyroid carcinoma.

Seven hundred sixty-one patients with operable differentiated thyroid carcinoma were treated between 1931 and 1970. Median follow-up time was 18 years and ranged from 5 to 40 years. Sixty-three percent of the patients were followed more than 15 years, and 46% were followed more than 20 years. Because resections usually spared sufficient thyroid tissue for homeostasis, thyroid hormone was not routinely prescribed after operations performed before 1960. Altogether 244 patients with papillary carcinoma and 76 patients with follicular carcinoma received thyroid hormone, while 296 patients with papillary carcinoma and 45 patients with follicular carcinoma did not receive thyroid hormone after operation. With papillary carcinoma, 14% of men greater than 40 and women greater than 50 years of age (high risk) but only 2% of men less than or equal to 40 years of age and women less than or equal to 50 years of age (low risk) died of disease (P 0.0001). Twenty-six percent of high-risk but only 4% of patients with low-risk follicular cancer died (P 0.0001). However, there was no statistically significant improvement in survival times with use of thyroid hormone when patients were categorized by risk group and pathology. These data support the importance of age and sex in previously described risk groups; these factors supersede the effects of adjuvant treatment. This absence of effect on survival times calls into question current recommendations for routine use of thyroid hormone after surgical therapy. Conceptually, such absence of adjunctive hormone effect on survival time after operation is similar to hormonal effects in other endocrine cancers, which may nevertheless provide good palliation in some cases.

Adenocarcinoma↗
PubMed1979

Risk factor analysis in differentiated thyroid cancer.

Six hundred patients with primary differentiated thyroid carcinoma had follow-up studies for a minimum of 15 years and a maximum of 45 years. Recurrence rate and death rate were significantly different in defined high-risk and low-risk groups of patients. These basic risk groups were defined by age and sex alone; low risk consisted of men 40 years of age and younger and women 50 years of age and younger whereas the high-risk group were older patients. Recurrence and death rates in patients at high risk were 33% and 27% while respective figures for patients at low risk were 11% and 4%. In more recent years these results have shown significant improvement. Basic risk group definition outweighed the effect of pathologic type, local disease extension, type of treatment, and site of recurrence or metastasis. For instance, radioactive iodine cured 70% of patients at low risk with metastatic disease but only 10% of patients at high risk. Less aggressive biologic behavior of thyroid cancer before the age of menopause implies that an estrogen-rich milieu may alter the effects of initiating and promoting factors in carcinogenesis. It also suggests that therapeutic trials of estrogen be undertaken in progressive metastatic differentiated thyroid cancer.

Adenocarcinoma↗
PubMed1976

Changing clinical, pathologic, therapeutic, and survival patterns in differentiated thyroid carcinoma.

Records of 792 patients with differentiated thyroid carcinoma seen at the Lahey Clinic Foundation over a 40-year period were analyzed; 631 patients had a minimum followup period of 15 years. Differentiated types currently constitute nearly 90% of thyroid carcinomas. The clinical presentation has improved substantially through the years, and the results of treatment generally have improved. The per cent of patients with primarily incurable and locally unresectable disease or distant metastases has decreased from 7% before 1950 to 1% currently, and this group resulted in almost one third of the total fatalities and one half of fatalities within the first 5 years after treatment. Clear relationships were demonstrated between older age, men, extraglandular extension, blood vessel invasion, major capsular involvement, multifocal disease, and higher mortality rates. Lymph node metastases were found to exert a protective effect in all categories of disease analyzed, and this effect was directly related to the number of lymph node metastases present such that no deaths occurred in those patients who had more than 10 node metastases. Surgical treatment recommended is subtotal thyroidectomy for patients at high risk of death from disease as defined by combinations of age, sex, and extraglandular extension. Patients at low risk or with small carcinomas can be treated satisfactorily by lobectomy. Lymph node resections should be of a limited type or a modified neck dissection and should be performed only therapeutically. No improvement, as judged by mortality or recurrence rates, could be demonstrated by the use of radio therapy after surgery, and its use should be discouraged. Thyroid hormone administered for suppression of endogenous thyroid-stimulating hormone production improved mortality rates significantly in patients with papillary and mixed forms of carcinoma in all age groups but did not affect survival in patients with follicular carcinoma of the thyroid.20

Adenocarcinoma↗