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Biomedical subjects

C A Ford

Publications and source records attributed to C A Ford.

At least 37 records · Page 2Linked to original sources
PubMed1997

Delivery of confidentiality assurances to adolescents by primary care physicians.

OBJECTIVE: To investigate physicians' practices in assuring confidentiality to adolescent patients. DESIGN: Mail survey. SETTING: California. PARTICIPANTS: Seven hundred eighty-six board-certified physicians in family practice, internal medicine, obstetrics and gynecology, or pediatrics (response rate, 65%). MAIN OUTCOME MEASURES: Physicians were asked the percentage of adolescent patients (15 to 18 years old) with whom they discuss confidentiality during routine visits and the content of their assurances of confidentiality. A clinical vignette assessed physicians' knowledge of legal guidelines for confidential treatment of adolescents. RESULTS: Physicians reported discussing confidentiality with 53% (on average) of their adolescent patients. Eleven percent of physicians did not discuss confidentiality with any adolescent patients. Hierarchical linear regression used to control for other physician demographic and practice factors showed that female physicians were more likely to discuss confidentiality than were male physicians (R2 change = 0.03, P < .001). There was also an association between specialty and discussing confidentiality (R2 change = .04, P < .001); obstetricians and gynecologists were more likely to discuss confidentiality than were other primary care physicians (beta = .21, P < .001). Among physicians who discussed confidentiality, 64% assured unconditional confidentiality and 36% assured conditional confidentiality. When asked about legal guidelines for managing a 15-year-old patient with a sexually transmitted disease, 63% of physicians responded correctly, 5% responded incorrectly, and 31% were unsure of management guidelines. CONCLUSIONS: Physicians do not consistently discuss confidentiality with their adolescent patients. Most of the physicians who discuss confidentiality, with adolescents assure unconditional confidentiality, which is inconsistent with professional guidelines or the legal limitations of confidentiality.

Adolescent↗
PubMed1997

Localisation of insulin-like growth factor receptors in skin follicles of sheep (Ovis aries) and changes during an induced growth cycle.

Pelage growth cycles are regulated by circulating prolactin in many mammals, but the intercellular mediators of this signaling are unknown. Binding sites for insulin-like growth factors (IGFs) were examined in sheep skin to show changes in distribution and abundance of IGF receptors associated with a prolactin stimulus and the subsequent hair follicle growth cycle. Follicle cycles were induced in New Zealand Wiltshire ewes by a surge in plasma prolactin following a 4-month period of prolactin suppression with bromocriptine. Eight treated and three control sheep were slaughtered at intervals over 43 days during the follicle growth cycle. At 12-20 days after the elevation of prolactin, wool follicles passed through brief catagen and telogen phases, followed by a return to anagen. IGF binding sites were localized in skin sections by incubation with 125I-IGF-I or 125I-IGF-II. Displacement with competitive binding inhibitors (unlabeled IGF-I, IGF-II, des(1-3)IGF-I, des(1-6)IGF-II, or insulin) and affinity cross-linking showed that these binding sites were predominantly IGF type 1 and type 2 (mannose-6-phosphate) receptors. The radioligands bound especially to follicle germinal cells and prekeratinocytes. Increases in specific binding of both radioligands were observed after the rise in prolactin, but prior to anatomical changes in follicles associated with cessation of growth. For IGF-I, highest binding density was observed during catagen in the germinal matrix and dermal papilla cells. For IGF-II, peak density occurred during late anagen/early catagen in the germinal matrix and during telogen in the dermal papilla. These cycle associated changes in receptor availability suggest that IGF receptors are involved in control of the wool growth.

Animals↗
PubMed1996

Persistent organochlorines in beluga whales (Delphinapterus leucas) from the St Lawrence River estuary--I. Concentrations and patterns of specific PCBs, chlorinated pesticides and polychlorinated dibenzo-p-dioxins and dibenzofurans.

Blubber samples from beluga whales (Delphinapterus leucas) in the St Lawrence River estuary were analysed for PCB congeners (ortho- and non-ortho-substituted) and other persistent organochlorines as well as chlorinated dibenzo-dioxins/furans (PCDD/Fs). Major individual components (mean concentrations > 1 microg g(-1)) were 4,4'-DDE, -DDD and -DDT, T12 (a toxaphene-related compound), trans-nonachlor, oxychlordane, mirex, HCB, tris(p-chlorophenyl) methane and dieldrin. Concentrations of SigmaPCBs (8.3-412 microg g(-1)), SigmaDDT (3.36-389 microg g(-1)) and mirex (0.18-6.8 microg g(-1)) were particularly elevated relative to other odontocetes in Canadian waters. SigmaDDT, PCBs (as Aroclor), mirex and T12 concentrations were positively correlated with age of adult females (> 10 years) but only weakly, or not significantly, correlated with age of adult males. PCDD/Fs were present at low ng kg(-1) levels and consisted mainly of penta- and hexachlorofurans, and hepta- and octachlorodioxin. CB126 (3,3',4,4',5-PCB) was the most prominent non-ortho-substituted PCB congener in beluga blubber. Total TCDD toxic equivalents averaged 330 ng kg(-1) in females and 1400 ng kg(-1) in males and were dominated by CB126, and the mono-ortho-substituted congeners CB105 and CB118. Biomagnification factors (BMFs) for mirex and SigmaPCB from fish to beluga ranged from 11 to 16, and were similar to BMFs in Arctic animals, indicating that elevated levels in St Lawrence animals are a consequence of relatively high levels of recalcitrant organochlorines in prey of the beluga in the St Lawrence river system.

Journal Article↗
PubMed1996

Anticipatory guidance regarding sex: views of virginal female adolescents.

PURPOSE: To explore virginal female adolescents' perceptions of potential discussions with physicians regarding sexuality. METHODS: Twenty-seven virginal female adolescents from an urban high school completed a semistructured interview that explored perceptions of: (1) physicians as resources for discussions about sexuality; (2) content of potential sexuality discussions with physicians; and (3) risks and benefits of sexuality discussions with physicians. The relative emphasis of responses across the sample are described by mean proportional scores (MPS). RESULTS: Health care professionals were spontaneously identified by 33% of participants as potential resources for discussions about sexuality issues. Participants' perceptions of the potential content of sexuality discussions with physicians emphasized prevention of pregnancy and sexually transmitted infections (STIs) (MPS = .37), and physician counseling (MPS = .22). These topics included alternatives to sex and sex refusal skills. The perceived benefits of such discussions were gaining information or assistance regarding pregnancy and STI prevention (MPS = .32), talking with an expert (MPS = .19), and having a supportive relationship with a caring adult (MPS = .16). Lack of confidentiality was perceived as the major risk of adolescent-physician sexuality discussions (MPS = .29). CONCLUSION: Virginal female adolescents perceive a range of topics regarding sexuality as appropriate for discussions with physicians. This should be considered when providing anticipatory guidance counseling to virginal patients regarding sex. Concerns about confidentiality need to be addressed.

Adolescent↗
PubMed1996

The relationship between age and gender in workers' attitudes toward sexual harassment.

The relationship between gender, age, and workers' attitudes toward sexual harassment as measured by the Sexual Harassment Attitudes Scale was examined. Participants were full-time workers employed at a local hardware-manufacturing company or a local utility company in New England. Results indicated that the women younger than 40 years old were significantly less tolerant of sexual harassment than older women were. In contrast, male workers' tolerance of sexual harassment decreased with age up until the age of 50 years, after which their tolerance level of sexual harassment increased significantly.

Adolescent↗
PubMed1995

Can seal eating explain elevated levels of PCBs and organochlorine pesticides in walrus blubber from eastern Hudson Bay (Canada)?

Walrus (Odobenus rosmarus) blubber samples from Inukjuak and Akulivik (East Hudson Bay), Foxe Basin (Igloolik and Hall Beach) and Loks Land (East Baffin Island) were analysed for PCB congeners (ortho and non-ortho substituted) and other persistent organochlorines (DDT, toxaphene, chlordanes, dieldrin, mirex), as well as chlorinated dioxins/furans, to document spatial trends in contaminants in Canadian Arctic marine biota. Samples from 19 of 53 individuals had concentrations of SigmaPCBs greater than 1000 ng g(-1) (wet wt); the remaining individuals had much lower concentrations (50-600 ng g(-1)). Highest concentrations were found in samples from Inukjuak where average concentrations in blubber of females (N = 9) were 1450 +/- 954 ng g(-1) toxaphene, 2750 +/- 1780 ng g(-1) SigmaCHLOR, 2160 +/- 925 ng g(-1) SigmaDDT and 4790 +/- 2380 ng g(-1) SigmaPCB. SigmaPCB and SigmaDDT concentrations greater than 1000 ng g(-1) were unexpected based on previous studies of walrus from Greenland and Alaska. Local contamination was ruled out because levels of all organochlorines were elevated in each animal from Inukjuak, and elevated levels were also found in animals from Akulivik and Loks Land. Walrus from Inukjuak had sigma13C and sigma15N values in muscle intermediate between those of ringed seals (Phoca hispida) and those of walrus from Akulivik with low organochlorine levels. There was a weak but significant correlation between and sigma15N and (log)SigmaPCB. The Inukjuak walrus also had higher proportions of highly chlorinated PCB congeners, and higher DDE/SigmaDDT ratios than walrus from Igloolik or Akulivik. The results suggest that the walrus with elevated organochlorines are feeding at a higher trophic level than those with low levels and are probably utilizing ringed seals for a portion of their diet.

Journal Article↗
PubMed1995

Ethanol- and threonine-induced hypertension in rats: a common mechanism.

OBJECTIVE: To investigate the effects of oral L-threonine and ethanol, precursor of endogenous acetaldehyde, on systolic blood pressure, cystolic free calcium ([Ca2+]i) and vascular calcium uptake in Wistar-Kyoto (WKY) rats. METHODS: Twenty-four male WKY rats aged eight weeks were divided into four groups of six animals each. Animals were given either water or 5% ethanol, 8% L-threonine or 8% L-glycine in drinking water for 15 weeks, animals were sacrificed, aortic rings were incubated in physiological buffer containing 45Ca2+ and uptake was measured after 20 mins. ([Ca2+]i in platelets was measured with a fluorescence [Ca2+]i indicator, FURA-2. Tissues were processed for morphological investigation. RESULTS: After 15 weeks, systolic blood pressure, platelet [Ca2+]i and aortic calcium uptake were all significantly higher (P < 0.001) in rats given either threonine or ethanol than in control rats given water or glycine. Animals in threonine or ethanol group also showed smooth muscle cell hyperplasia, with some thickening of the wall and narrowing of the lumen in small arteries and arterioles of the kidney. Glycine treatment did not cause any of these changes in rats. CONCLUSION: These results suggest that acetaldehyde may be a common cause of both ethanol- and threonine-induced hypertension.

Animals↗
PubMed1995

Control of sexually transmitted diseases in adolescents: the clinician's role.

Sexually transmitted diseases common in the adolescent population are associated with significant acute morbidity, complications, and long-term sequelae. Clinicians have the opportunity to play a unique and important role in the control of STD rates among adolescents. Not only are clinicians in a position to routinely discuss healthy sexual development, decision making, and primary STD prevention, they are also in a position to effectively diagnose and manage STDs among both asymptomatic and symptomatic adolescents. Addressing issues related to sexuality and STDs in a consistent and repetitive manner during routine visits will likely increase physician proficiency in this important area of clinical care of adolescents, as well as increase adolescents' recognition of the clinician as a valuable resource.

Adolescent↗
PubMed1994

Fructose-induced hypertension, hypertriglyceridemia and elevated cytosolic calcium in rats: prevention by deuterium oxide.

We examined the effect of 5% deuterium oxide (D20) in drinking water on systolic blood pressure, platelet cytosolic free calcium, aortic calcium uptake and plasma insulin, glucose and triglycerides in rats with fructose-induced hypertension. Eighteen male Wistar-Kyoto (WKY) rats, age 8 weeks, were divided into 3 groups of 6 animals each. Animals in group I were given water; group II, 8% fructose and group III, 8% fructose + 5% D20 as their drinking water for the next 15 weeks. Systolic blood pressure in the fructose treated rats was significantly higher (p < 0.01) than in animals on water after 2 weeks and remained higher throughout the study. At 15 weeks, systolic blood pressure, platelet cytosolic calcium, aortic calcium uptake and plasma glucose, insulin and triglycerides were significantly higher (p < 0.01) in the fructose treated rats compared with rats from other groups. Deuterium oxide given together with fructose prevented development of high blood pressure and the associated increase in platelet cytosolic calcium, aortic calcium uptake and plasma triglycerides. D20 treatment did not prevent fructose induced increases in plasma insulin and glucose. The parallel increase in systolic blood pressure, cytosolic free calcium, and in vascular calcium uptake suggests that an increased cytosolic free calcium is involved in the pathophysiology of hypertension. D20 prevents this hypertension by normalizing cytosolic free calcium.

Animals↗
PubMed1994

Oral treatment with low molecular weight heparin normalizes blood pressure in hypertensive rats.

Increased calcium uptake in vascular tissue, leading to elevated cytosolic free calcium has been implicated in the pathophysiology of hypertension. This study examined the effect of oral low molecular weight heparin (Logiparin) on systolic blood pressure, platelet cytosolic free calcium and aortic calcium uptake in spontaneously hypertensive rats. Starting at age 12 weeks, spontaneously hypertensive rats were divided into three groups of six animals each. The drinking water of groups 1, 2 and 3 was replaced by 100% H2O, 0.5 mg (low dose) or 1 mg (high dose) low molecular weight heparin/ml H2O, respectively, for next 11 weeks. Six normotensive Wistar-Kyoto rats (age 12 weeks) on H2O and six on low dose heparin in H2O were used as controls. At age 23 weeks, increase in systolic blood pressure, platelet cytosolic free calcium and aortic calcium uptake in spontaneously hypertensive rats was significantly lowered by low dose LMW heparin as compared to spontaneously hypertensive rats on H2O, but was significantly higher than Wistar-Kyoto rats on H2O and LMW heparin. This dose of heparin did not have any effect on these parameters in normotensive Wistar-Kyoto rats. High dose LMW heparin normalized the elevated platelet cytosolic free calcium, aortic calcium uptake and systolic blood pressure in spontaneously hypertensive rats, but it had a limited effect on adverse renal vascular changes. Oral low molecular weight heparin did not cause any abnormal hematological, biochemical or pathological changes in rats.

Administration, Oral↗
PubMed1993

Administration of melanotropic peptides during gestation in the rodent.

A potent analogue of alpha-MSH (alpha-melanocyte stimulating hormone, S-alpha-melanotropin), [Nle4,D-Phe7] alpha-MSH, induces darkening of follicular melanocytes when injected or applied topically to the skin of mice [1]. This analogue also results in increased pigmentation when injected subcutaneously (s.c.) in humans. Toxicological studies have been performed on rodent models with administration topically or by intraperitoneal (i.p.) injection. No toxicity was observed and no pathological or significant biochemical changes were found. However there has been some controversy in the literature revolving around whether or not alpha-MSH is trophic for fetal growth and whether the hormone affects fetal adrenal development. These questions have been addressed in this study. All previous studies on the possible reproductive function of alpha-MSH have involved use of the natural hormone only. This is first to demonstrate the effects of the more potent analogue. The rat was used as the animal model to determine if the potent analogue of alpha-MSH affects events in gestation and embryonic fetal development and to determine if the analogue was a developmental toxicant. This study also examines the effect of a melanotropic peptide delivered directly to the conceptus in utero during organogenesis. No changes were found in the parameters examined (sex ratio, weight, morphology or histology, etc.) between treated and control fetuses. There was no evidence of premature parturition or pigmentation changes in the fetuses. The work reported in this study is of relevance if such a melanotropic peptide is to be used in women of childbearing age to induce pigmentation of the skin. Although the present results cannot necessarily be extrapolated to humans, indications are that, in rodents at least, [Nle4,D-Phe7] alpha-MSH and natural alpha-MSH have no adverse effects when administered during gestation and fetal development.

Animals↗
PubMed1992

Organochlorine contaminants in narwhal (Monodon monoceros) from the Canadian Arctic.

Organochlorine pesticides (DDT, chlordane, polychlorinated camphenes (PCCs), dieldrin, hexachloroheclohexanes (SigmaHCH), mirex), polychlorinated biphenyl congeners (PCBs) and chlorobenzenes (SigmaCBz) were determined in blubber and liver of narwhal (Monodon monoceros) collected during 1982-1983 from Pond Inlet on northern Baffin Island in the Canadian Arctic. PCCs were the predominate organochlorines in narwhal blubber, ranging in concentration from 2990 to 13 200 ng g(-1) (wet wt) in males and from 1910 to 8390 ng g(-1) in females. PCCs consisted of two major components, an octachlorobornane and a nonachlorobornane with gas chromatographic retention times of 1.05 and 1.22, relative to 4,4'-DDE. SigmaPCB concentrations in blubber ranged from 2250 to 7290 ng g(-1) in males and from 894 to 5710 ng g(-1) in females. Seven PCB congeners (tetra-, penta- and hexachlorobiphenyls) accounted for 45% of total PCB (SigmaPCB) in narwhal blubber. Narwhal had 1.4- to 8.6-fold higher ratios of tetra- and pentachlorobiphenyls to PCB-153 (2,2',4,4',5,5'-hexachlorobiphenyl), lower 4,4'-DDE/SigmaDDT ratios and lower proportions of trans-nonachlor to total chlordane components than reported for odontocetes living in more contaminated environments. Mean SigmaPCB concentrations in narwhal were 6- to 15-fold lower than in dolphins from the Canadian east coast and belugas from the St Lawrence River estuary, respectively, while PCC levels were from 4- to about 2-fold lower, and SigmaHCH, dieldrin and SigmaCBz differed by <2-fold. The pattern of organochlorines in narwhal tissues suggests they are exposed to proportionally more volatile compounds, and may have less capacity to metabolize some of these compounds, relative to odontocetes living nearer sources of these contaminants.

Journal Article↗
PubMed1991

The loss of 45Ca2+ associated with prolactin release from the tilapia (Oreochromis mossambicus) rostral pars distalis.

The relationship between tritium 3H-labeled prolactin (PRL) release and the loss of tissue-associated 45Ca2+ was examined in the tilapia rostral pars distalis (RPD) using perifusion incubation under conditions which inhibit or stimulate PRL release. Depolarizing [K+] (56 mM) and hyposmotic medium (280 mOsmolal) increased both the release of [3H]PRL and the loss of 45Ca2+. The responses to high [K+] were faster and shorter in duration than those produced by reduced osmotic pressure. The depletion of Ca2+ from the incubation medium with 2 mM EGTA suppressed the [3H]PRL response evoked by high [K+] or reduced osmotic pressure. Exposing the tissues to Ca(2+)-depleted medium in the absence of high [K+] or reduced osmotic pressure produced a sharp, but brief, increase in 45Ca2+ loss. Cobalt (10(-3) M), a competitive inhibitor of calcium-mediated processes, inhibited the [3H]PRL response to hyposmotic medium and to high [K+]. Cobalt also diminished the increased loss of 45Ca2+ evoked by exposure to reduced osmotic pressure, but was ineffective in altering responses to high [K+]. Methoxyverapamil (D600; 10(-5) M), a blocker of certain voltage-sensitive Ca2+ channels, did not alter either the [3H]PRL or the 45Ca2+ responses to high [K+] and reduced osmotic pressure. Taken together with our earlier studies, the present findings suggest that exposure to high [K+] or hyposmotic medium produces rapid changes in the Ca2+ metabolism of the tilapia RPD that are linked to the stimulation of PRL secretion. Nevertheless, the increased 45Ca2+ loss, but not [3H]PRL release, upon exposure to Ca(2+)-depleted media suggests that Ca2+ loss may not always reflect intracellular events that lead to PRL release.

Animals↗
PubMed1990

Primary lung cancer: characterization and survival of 1024 patients treated in a single institution.

This report describes the presenting features, smoking history, diagnostic techniques and their yields, histological typing and tumor-node-metastases (TNM) staging for a cohort of 1024 Australian patients with primary lung cancer. It also includes survival data for the group as a whole and for subgroups of patients based on clinical stage, histology, treatment modality and postsurgical stage. Ninety-six per cent of patients had smoked. A much higher proportion of patients with adenocarcinoma had smoked than has commonly been believed. In surgically treated patients, stage, but not histological type or age, was related to survival. Approximately one-third of all patients had such advanced disease that no treatment to the primary site was offered.

Actuarial Analysis↗
PubMed1990

Effects of depolarizing concentrations of K+ and reduced osmotic pressure on 45Ca2+ accumulation by the rostral pars distalis of the tilapia (Oreochromis mossambicus).

The accumulation of 45Ca2+ into tilapia prolactin (PRL) tissue was examined under conditions which alter prolactin release. In initial experiments, PRL tissue was incubated in medium containing 12 microCi/ml 45Ca2+ in hyperosmotic medium (355 mOsmolal). Under these conditions, 45Ca2+ accumulated steadily, reaching a plateau within 15-20 min. Subsequent exposure to La3+, which displaces Ca2+ from superficial pools in a wide variety of tissues, rapidly (within 5 min) removed nearly 70% of the 45Ca2+ associated with the tissue. Following this initial removal of 45Ca2+, the level of 45Ca2+ in the PRL tissue remained constant, and is referred to as the La3(+)-resistant pool of Ca2+. This pool of Ca2+ is thought to reflect the entry rate of Ca2+ from extracellular sources. Prolactin tissue exposed to hyposmotic medium or to depolarizing [K+], which stimulates PRL release, significantly increased 45Ca2+ accumulation in this La3(+)-resistant pool. These results indicate that reduced osmotic pressure and depolarization may alter release from tilapia PRL cells, in part, through their ability to increase the entry of extracellular Ca2+.

Animals↗
PubMed1989

Molecular screening for haemoglobin constant spring.

Haemoglobin H/Constant Spring is an important cause of severe haemoglobin H disease, but the Constant Spring protein is difficult to detect by electrophoresis. A technique for allele specific polymerase chain amplification of the 3'-end of the alpha 2 globin gene improved detection of the alpha cs alpha haemoglobin variant in DNA samples by slot-blot hybridisation. The alpha cs alpha mutation was confirmed in subjects that had been previously diagnosed by haemoglobin electrophoresis, and it was also detected in patients who were negative by protein electrophoresis. 10 of 103 unrelated Laotians with HbE were alpha cs alpha heterozygotes. Of these, 3 were negative to the normal probe because they had -alpha 3.7/alpha cs alpha with a single alpha globin deletion. 5 samples did not amplify or hybridise to either probe because they had deletions of both alpha 2 globin regions. The gene frequency for alpha cs alpha is about 0.05 for Laotians. This technique, which is highly specific and sensitive for rapid detection of the alpha cs alpha mutation, is suitable for clinical diagnoses and population studies. The true incidence of alpha cs alpha may prove to be greater than previously suspected from protein electrophoresis.

Alpha-Globulins↗
PubMed1988

The different types of alpha-thalassemia: practical and genetic aspects.

From May 1985 to October 1987, 1,564 Southeast Asians living in Hawaii were screened for hereditary anemias. Microcytosis was determined by electronic red cell indices and morphology; iron deficiency was ruled out by normal red cell distribution width and normal protoporphyrin levels; Hb E was determined by electrophoresis; beta-thalassemia (thal) heterozygotes were identified by raised Hb A2 on column chromatography. alpha-Thalassemia heterozygotes were diagnosed by exclusion. Family studies helped identify or confirm diagnoses, especially for the alpha-thal-2 heterozygotes (-alpha/alpha alpha) and homozygotes (-alpha/-alpha). Provisional diagnoses are being checked by DNA analyses. Iron deficiency prevented detection of possibly coexisting alpha-thalassemias in 97 individuals. Technical problems included the obscuring of standard criteria for recognizing the alpha-thal variants by the presence of Hb E or beta-thal. In such cases, alpha-thal could only be detected by family studies or DNA analyses. Problems with hemoglobin (Hb) electrophoresis included Hb H migrating beyond the edge of the strip if incubation was not closely monitored, and difficulty in detecting the small amounts of unstable Hb Constant Spring. DNA analyses also had limitations, since the nondeletion alpha-thalassemias would not be detected by routine Southern blotting. DNA analyses suggested that about 50% of presumed alpha-thalassemias were alpha-thal-2 (-alpha/alpha alpha) variants, and a corresponding number of alpha-thal-2 variants were among the apparent normals. Gene frequencies in the unselected Lao subjects were approximately 0.2 for Hb E, at least 0.1 for (-alpha), usually a rightward (alpha -3.7) type, 0.04 for (-), and 0.01 for a beta-thal. Multistep screening for the alpha- and beta-thalassemias was an effective and efficient strategy.

Asia, Southeastern↗