Nipple candidiasis among breastfeeding mothers. Case-control study of predisposing factors.

OBJECTIVE: To investigate factors that predispose breastfeeding mothers to nipple candidiasis. DESIGN: A retrospective case-control study of women attending the Calgary Breastfeeding Clinic. SETTING: Ambulatory breastfeeding referral centre. PARTICIPANTS: All women (105) who attended the clinic during a 3.5-month study period. All were referred for problems with breastfeeding; 27 (the case group) had positive diagnostic criteria for nipple candidiasis. The other 78 formed a control group. MAIN OUTCOME MEASURE: A patient information sheet, completed while taking a medical history, recorded the presence or absence of four possible predisposing factors. Two infant variables were also noted on physical examination. Patients were diagnosed as having or not having nipple candidiasis on the basis of specific clinical criteria, and statistics on other variables were compared for those with positive and with negative diagnoses. RESULTS: A statistically significant correlation (P < 0.05) was found between nipple candidiasis and three factors: vaginal candidiasis (P = 0.001), previous antibiotic use (P = 0.036), and nipple trauma (P = 0.001). CONCLUSIONS: Further research is required to establish clear causality. However, we recommend that physicians be suspicious of nipple candidiasis; avoid antibiotics or use the shortest effective course; treat yeast vaginitis during the third trimester and after delivery aggressively; and treat mothers for nipple yeast if babies have oral or diaper candidiasis. Breastfeeding mothers can also be counseled in preventive measures.

The calciotropic hormone response to changes in serum calcium during exercise in female long distance runners.

The purpose of this study was to evaluate the effects of 45 min of submaximal running on calciotropic hormone levels in female long distance runners. Fourteen long distance runners and six sedentary controls (less than three exercise sessions per week) had bone mineral density (BMD) of the lumbar spine (L2-L4), femoral neck, and tibia measured by dual photon absorptiometry. All of the sedentary controls and eight runners (NormR) had BMD values within the normal range for women of their age. The remaining six runners had BMD L2-L4 measures greater than 1 SD below normal values and were classified as the low bone density group (LowR). Subjects were tested for their calciotropic hormone response to submaximal running using both an oral calcium load (dairy product), to induce a significant elevation in serum calcium, and no calcium load. In both exercise tests, serum calcium rose in NormR and LowR, with a greater increase induced by the oral calcium load. In NormR, the increase in serum calcium resulted in decreased PTH levels, with small increases in calcitonin levels. In contrast, LowR showed significant (P < 0.05) increases in PTH levels, with concurrent decreases in calcitonin levels. The changes in calciotropic hormone levels were shown to be significantly associated with BMD. Our results suggest that in well trained female runners with low spinal bone density, long distance running may aggravate this condition through the effect of exercise-related elevations of PTH on bone turnover. Alterations in the homeostatic control mechanisms for calcium during exercise should also be considered in the clinical assessment of female runners with spinal osteopenia.

Activation and inhibition of protein kinase C in cultured bovine parathyroid cells: effect on the release of C-terminal fragments of parathyroid hormone.

The response of the parathyroid gland to low Ca2+ may be mediated in part by protein kinase C (PKC). We assessed the effect of two PKC activators, SC-9 and SC-10, and one PKC inhibitor, H-7, on Ca(2+)-regulated PTH release and degradation in primary cultures of bovine parathyroid cells. Both SC-9 and SC-10 stimulated PTH release, compared to high Ca2+ alone, in parathyroid cells incubated in high Ca2+, with maximal PTH release of at least twofold occurring at a concentration of either activator of 10 nM (p less than 0.05). We have previously shown that another PKC activator, PMA, not only enhances PTH release in the presence of high Ca2+ but suppresses low Ca(2+)-stimulated PTH secretion. In the present study, neither SC-9 nor SC-10 caused a comparable suppression of PTH release at low Ca2+. However, the PKC inhibitor, H-7 (1 microM), blocked low Ca(2+)-stimulated (compared to the low Ca2+ control) PTH secretion by approximately 50% (p less than 0.01) and did not affect high Ca2+ suppression of PTH secretion. H-7 (1 microM) was able to oppose the stimulation of PTH release by the PKC activators SC-9, SC-10, and PMA at high Ca2+ and negated the PTH release-inhibiting effect of PMA at low Ca2+. Culture medium from these experiments was subjected to reversed-phase HPLC and the eluted fractions analyzed by RIA for the presence of intact and C-terminal fragments of PTH.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of phorbol myristate acetate on the intracellular degradation of bovine parathyroid hormone.

The suppression of PTH release by high extracellular calcium (Ca2+) has been associated with secretion of biologically inactive carboxyl-terminal fragments of PTH (C-PTH), while relatively more intact PTH is released under low extracellular Ca2+ conditions. In the presence of high extracellular Ca2+, phorbol myristate acetate (PMA) has been shown to stimulate PTH release to levels observed at low Ca2+, suggesting that protein kinase-C (PKC) is involved in the regulation of PTH secretion. We have examined the effect of PMA on PTH secretion and the release of PTH fragments at high and low calcium concentrations. Primary cultures of bovine parathyroid cells were incubated for 90 min in 0.5 mM (low) or 2.0 mM (high) Ca2+ with or without 1.6 microM PMA. Reverse phase HPLC using an 18-60% gradient of acetonitrile in 0.1% trifluoroacetic acid was performed on the medium from these incubations, and the eluant fractions were analyzed with a carboxyl (C)-terminal-specific PTH RIA. Medium from cultures exposed to low Ca2+ exhibited two large peaks of PTH immunoreactivity, coeluting with intact PTH-(1-84) and a synthetic human C-PTH-(39-84). PMA treatment at low Ca2+ resulted in the secretion of a greatly reduced amount of intact PTH, suggesting that PKC may increase the production of PTH fragment. At high extracellular Ca2+ PMA caused an increase in total immunoreactive PTH release similar to that seen at low Ca2+. However, on HPLC analysis, proportionally more PTH eluted in the position of the C-PTH fragment than was seen with low Ca2+ stimulation of PTH secretion. It, therefore, appears that the degradation of PTH to C-PTH may be linked to activation of PKC and can be separated from the Ca2+ regulation of PTH release occurring at the cell membrane.

A cytotoxic monoclonal autoantibody from the BB rat which binds an islet cell surface protein.

The BB rat provides an excellent animal model for type 1 (insulin-dependent) diabetes mellitus. Cytotoxic autoantibodies against pancreatic beta cells have been found in the sera of both patients with type 1 (insulin-dependent) diabetes and BB rats. These antibodies have been implicated in the pathogenesis of the disease. In this study, a monoclonal autoantibody, designated KT1, has been developed by the fusion of spleen cells from a BB rat and a mouse myeloma cell line. KT1 was found to be of the immunoglobulin M isotype and reacted specifically with islet cells. In microcytotoxicity assays KT1 was shown to mediate complement-dependent lysis of approximately 30% of a rat insulinoma cell line and 25% of rat pancreatic islet cells in culture. It did not cause lysis of the other cell lines tested. KT1 has been demonstrated, by indirect immunofluorescence, to bind specifically to a cell surface antigen on live and acetone-fixed islet cell cultures from Wistar rat neonates and to rat insulinoma cells. Western blotting experiments revealed reaction to a 68-kDa protein from rat insulinoma cell extracts. This monoclonal antibody may have clinical relevance as it exhibits properties similar to the islet cell surface antibodies present in the sera of BB rats.

Studies on the correlation between the presence of cytotoxic islet cell surface antibody and the incidence of overt diabetes in BB rats.

Antibodies directed to the surface of islet cells are often present in the sera of both humans with insulin-dependent diabetes and the BioBreeding (BB) rat. These autoantibodies have been implicated in the disease process although the correlation between the presence of islet cell surface antibodies (ICSA) and diabetes is controversial. In this study the presence of cytotoxic islet cell surface antibody (ICSA) was examined in 65 BB rats from 60-150 days of age. Blood was collected every 7-10 days and sera were assayed by a 51Cr-release assay using rat insulinoma cells (RINm5F) as target cells. Onset of diabetes was determined by bi-weekly urinalysis. The incidence of diabetes was 51%. While 29% of the rats exhibited cytotoxic ICSA and diabetes, 22% were overtly diabetic without showing any measurable ICSA. An additional 22% showed ICSA but did not become diabetic in the time period studied. These results suggest no correlation between cytotoxic ICSA and diabetes in our BB rat colony.

Acetylcholine receptor aggregation parallels the deposition of a basal lamina proteoglycan during development of the neuromuscular junction.

To determine the time course of synaptic differentiation, we made successive observations on identified, nerve-contacted muscle cells developing in culture. The cultures had either been stained with fluorescent alpha-bungarotoxin, or were maintained in the presence of a fluorescent monoclonal antibody. These probes are directed at acetylcholine receptors (AChR) and a basal lamina proteoglycan, substances that show nearly congruent surface organizations at the adult neuromuscular junction. In other experiments individual muscle cells developing in culture were selected at different stages of AChR accumulation and examined in the electron microscope after serial sectioning along the entire path of nerve-muscle contact. The results indicate that the nerve-induced formation of AChR aggregates and adjacent plaques of proteoglycan is closely coupled throughout early stages of synapse formation. Developing junctional accumulations of AChR and proteoglycan appeared and grew progressively, throughout a perineural zone that extended along the muscle surface for several micrometers on either side of the nerve process. Unlike junctional AChR accumulations, which disappeared within a day of denervation, both junctional and extrajunctional proteoglycan deposits were stable in size and morphology. Junctional proteoglycan deposits appeared to correspond to discrete ultrastructural plaques of basal lamina, which were initially separated by broad expanses of lamina-free muscle surface. The extent of this basal lamina, and a corresponding thickening of the postsynaptic membrane, also increased during the accumulation of AChR and proteoglycan along the path of nerve contact. Presynaptic differentiation of synaptic vesicle clusters became detectable at the developing neuromuscular junction only after the formation of postsynaptic plaques containing both AChR and proteoglycan. It is concluded that motor nerves induce a gradual formation and growth of AChR aggregates and stable basal lamina proteoglycan deposits on the muscle surface during development of the neuromuscular junction.