Prevalence of multiple sclerosis in a residential area bordering an oil refinery.

BACKGROUND: Community concerns about a potential excess of multiple sclerosis (MS) prompted this study. OBJECTIVE: To determine the period prevalence of MS in a community bordering a closed oil refinery and a control community. METHODS: Cases seen by a neurologist during 1998 to 2001 were obtained from area neurologists and hospital discharge data. Population data were obtained from the year 2000 US Census. Patient data were abstracted by a trained abstractor onto a standardized report form. A consulting neurologist reviewed the form and made a final diagnosis using the Poser criteria plus the category of presumed. Age-adjusted prevalence rates and rates of agreement were calculated. RESULTS: The direct age-adjusted period prevalence for both sexes and all races for the entire study area was 113 per 100,000 (95% CI = 93 to 136). For white subjects only, the prevalence was 123 per 100,000 (95% CI = 102 to 147). With use of an indirect method of age adjustment, the number of observed cases in the community bordering the refinery was similar to the number of cases expected (standardized morbidity ratio = 130.8, 95% CI = 62.3 to 199.3), based on rates from the comparison area. The agreement between the treating neurologist (for definite plus probable cases) and the consulting neurologist (for definite plus probable plus presumed cases) was good (kappa = 0.5733). CONCLUSIONS: The prevalence of multiple sclerosis (MS) for this area was generally consistent with prevalence estimates calculated in previous studies in other areas. No significant excess was seen in the exposed area. MS was more prevalent in females than in males. The overall agreement between the consulting and treating neurologist was good.

Influence of oocyte-secreted factors and culture duration on the metabolic activity of bovine cumulus cell complexes.

Intracellular communication between the cumulus cell complex and the oocyte is essential for numerous processes during oocyte maturation. The aim of this study was to determine the interaction between oocyte-secreted factors and the metabolic activity of bovine cumulus cell complexes during in vitro maturation (IVM). Cumulus-oocyte complexes (COCs) were aspirated from ovaries derived from an abattoir and divided into four treatment groups: (i) intact COCs, (ii) oocytectomized complexes (OOX), in which the ooplasm was microsurgically removed, (iii) OOX co-cultured with denuded oocytes (OOX+DO) and (iv) DO. The complexes were cultured individually in IVM media. After 0-4, 10-14 and 20-24 h of culture, the utilization of oxygen, glucose, pyruvate and L-lactate by the complexes was measured. The metabolic activity of the DO was undetectable. There were no significant differences in metabolic measurement among any of the treatment groups, indicating that the metabolism of the cumulus complex is not affected by the presence of the oocyte. When metabolic activity for the complexes was analysed relative to time in culture, there was an approximate twofold increase in the consumption of oxygen, glucose and pyruvate over the 24 h period (P<0.05), although production of L-lactate remained constant. The relationship between total glucose uptake and L-lactate production indicated that the majority of glucose consumed at the start of culture was being utilized via glycolysis, but by the cessation of the maturation period, there was significant utilization of glucose elsewhere, possibly for the formation of cumulus extracellular matrix. These results indicate that metabolism of COC does not reflect biochemical activity of the oocyte. Nevertheless, the metabolic requirements of the COC increase throughout maturation.

Effects of in-vivo and in-vitro environments on the metabolism of the cumulus-oocyte complex and its influence on oocyte developmental capacity.

There has been an improvement in the blastocyst rates achieved following in-vitro embryo production that can largely be attributed to improved embryo culture conditions based on an increased knowledge of the in-vivo environment, as well as the metabolic needs of the embryo. Despite this, in-vitro oocyte maturation (IVM) conditions have remained largely unchanged. Within the antral follicle, numerous events affect oocyte maturation and the acquisition of developmental competency, including: interactions between somatic cells of the follicle (in particular cumulus cells) and the oocyte; the composition of follicular fluid; and the temperature and vascularity of the follicular environment. Many of these factors change with follicle size and oocyte growth. In contrast, culture conditions for IVM are based on somatic cells that often do not reflect the follicular environment, and/or have complex compositions or additives such as macromolecule supplements that are undefined in nature. Metabolites included in media such as glucose, pyruvate, oxygen and amino acids have been shown to have differential influences on oocyte maturation and competency. Manipulation of these factors and application of gained knowledge of the in-vivo environment may result in improved in-vitro oocyte maturation and overall in-vitro embryo production.

The effect of external pituitary irradiation on elevated serum prolactin levels in patients with pituitary macroadenomas.

The response of serum prolactin to external radiotherapy was studied in 58 patients (32 women) with pituitary tumours, aged between 16 and 75 years. Forty-four patients underwent pituitary surgery before radiotherapy. Six patients were irradiated with a regimen of 20 Gy in eight fractions over 10-11 days and the remainder received 35-42.5 Gy in 15 fractions over 20-22 days. Following radiotherapy, 44 patients received additional treatment with dopaminergic agonists. Prolactin levels ranged from 1078 to 491,000 mU/l (median 11,750 mU/l) before radiotherapy and all but three patients showed a fall in serum prolactin (measured 4 weeks after stopping bromocriptine in those on dopamine agonist therapy) during observation over periods of up to 154 months. All patients had evidence of pituitary fossa erosion or expansion at presentation and large tumours (Hardy-Vezina Grade 3-4) were more common in male patients (chi 2 = 10.08, p less than 0.01). The rate of fall of serum prolactin levels was greater in patients with true prolactin-secreting tumours when compared with those who had stalk or hypothalamic damage (p less than 0.005). The rate of decline of serum prolactin was also significantly related to the pre-radiotherapy value (rho = 0.519, p less than 0.01). A serum prolactin level less than 500 mU/l was achieved in 31 out of 44 patients treated with radiotherapy and dopaminergic agonist but only nine remained normoprolactinaemic when medication was discontinued for 4 weeks or more. The serum prolactin level fell permanently to less than 500 mU/l in two of 14 patients treated with radiotherapy only. Actuarial analysis of data from all patients indicated a 50 per cent probability that prolactin would be reduced to less than 500 mU/l by 10 years; this increased to 58 per cent for patients with smaller tumours (Hardy-Vezina grade 2).(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term follow-up of low-dose external pituitary irradiation for Cushing's disease.

Twenty-four patients (three male) with Cushing's disease, aged between 11 and 67 years, were treated with low-dose external pituitary irradiation (20 Gy in eight fractions over 10-12 days) and followed for between 13 and 171 months (median 93 months). Eleven patients (46%) went into remission 4-36 months after irradiation, but five subsequently relapsed. Two of these received no further active treatment, one underwent successful pituitary surgery, one underwent a second course of low-dose external irradiation (as yet unsuccessful) and one has been treated with metyrapone for a total of 75 months. One of the 13 patients who did not respond received a further course of low-dose pituitary irradiation with prompt remission and two have received metyrapone for 41 months and 15 years without ill effect. One patient died from cerebrovascular disease. The remaining nine patients underwent bilateral adrenalectomy (one after unsuccessful pituitary surgery) with rapid resolution of hypercortisolism. Five of these patients have developed hyperpigmentation and elevated ACTH levels (range 505-1150 ng/l). A pituitary microadenoma has been demonstrated on CT scan in three and successfully removed by microadenomectomy. In the present series, the low incidence of radiation-induced hypopituitarism and absence of other complications attributable to radiotherapy suggest that low-dose pituitary irradiation may be a useful treatment option in selected patients. However, long-term follow-up has demonstrated a high relapse rate and failure to prevent Nelson's syndrome in adrenalectomized patients, indicating that it should not be used as primary treatment in preference to selective adenomectomy.

Chronic toxicity and oncogenicity studies of Macrodantin in Sprague-Dawley rats.

Chronic toxicity and oncogenicity studies of nitrofurantoin formulated as Macrodantin have been undertaken. The doses ranged from 12 to 116 mg/kg body weight/day. At 116 mg/kg/day, female rats showed a decreased weight gain. In the high-dose groups in the chronic toxicity study (males, 81 mg/kg/day; females, 116 mg/kg/day) there was an increase in testicular degeneration, sciatic nerve degeneration and fibrosis in both males and females, and an increase in focal biliary proliferation in females. There was no evidence of renal toxicity. There was no compound-related effect upon neoplasms at any site. In the oncogenicity study, an increase in focal biliary proliferation was observed in females given 31 or 56 mg/kg/day. There was no treatment-related increase in the incidence of neoplasms at any site. In particular there was no increase in the incidence of mammary or renal tumours. The observations in these studies indicate that therapeutic uses of Macrodantin would not present a carcinogenic hazard to man.

Low-dose pituitary irradiation for acromegaly.

External radiotherapy has been used as primary treatment for acromegaly in 29 patients and in combination with surgery in 41 patients in whom growth hormone levels remained elevated postoperatively. Fourteen further patients who did not receive radiotherapy have also been studied, four of whom had undergone surgical treatment. Radiotherapy schedules consisted of 20 Gy in eight fractions over 11 days (n = 23) or 35-40 Gy in 15 fractions over 21 days (n = 47). Growth hormone hypersecretion was either unchanged or increased with time in non-irradiated patients. In those patients who underwent radiotherapy, the likelihood of the mean GH level during GTT falling to less than 5 mU/l was unaffected by the total dose of radiation administered. However, patients with a pre-radiotherapy GH level of less than 30 mU/l showed a significantly increased probability of achieving a post- radiotherapy GH level less than 5 mU/l (P = 0.002). Previous surgery, initial serum prolactin and the age or sex of the patient did not predict the successful outcome of radiotherapy. In view of the known dose dependency of radiation-induced hypopituitarism, lower radiation dose schedules (20 Gy; eight fractions in 11 days) can be used in acromegaly with some benefit, especially in younger patients. However, all patients should undergo operative removal of as much GH-secreting tissue as possible, in order to lower GH levels and increase the probability of achieving a cure following radiotherapy.

Oncogenicity study of macrodantin in Swiss mice.

A carcinogenicity study of nitrofurantoin formulated as Macrodantin was undertaken. The doses used were 0.0, 50.0, 100.0 and 200.0 mg/kg/day. Increased mortality was observed in male mice given 200 mg/kg/day. Chronic toxicity was observed in the kidneys of male mice: the normally occurring chronic nephropathy was somewhat increased in severity. The gonads of both male and female mice showed evidence of atrophy and degeneration. The ovaries showed an increased incidence of multilobular cysts but no evidence of neoplasia. A significantly higher incidence of malignant lymphoma in the top-dose males was offset by a non-significant difference in the opposite direction in females. Reasons are given for regarding this as a chance finding. The observations in this study indicate that the therapeutic uses of nitrofurantoin would not present a carcinogenic hazard to man.

Radiation-induced hypopituitarism is dose-dependent.

Radiation-induced hypopituitarism has been studied prospectively for up to 12 years in 251 adult patients treated for pituitary disease with external radiotherapy, ranging in dose from 20 Gy in eight fractions over 11 days to 45 Gy in 15 fractions over 21 days. Ten further patients were studied 2-4 years after whole-body irradiation for haematological malignancies using 12 Gy in six fractions over 3 days and seven patients were studied 3-11 years after whole-brain radiotherapy for a primary brain tumour (30 Gy, eight fractions, 11 days). Five years after treatment, patients who received 20 Gy had an incidence of TSH deficiency of 9% and in patients treated with 35-37 Gy, 40 Gy and 42-45 Gy, the incidence of TSH deficiency (22, 35 and 52% respectively) increased significantly (P less than 0.001) with increasing dose. A similar relationship was observed for both ACTH and gonadotrophin deficiencies when the 20 Gy group was compared to patients treated with 35-45 Gy (P less than 0.01 and P less than 0.05 respectively). Growth hormone deficiency was universal by 5 years over the dose range 35-45 Gy. In seven patients who were treated with 30 Gy in eight fractions over 11 days, deficiencies were observed at a similar frequency to the 40 Gy group (15 fractions, 21 days). No evidence of pituitary dysfunction was detected in the ten patients who received 12 Gy (six fractions, 3 days). Both total radiation dose and fractionation schedule may determine the incidence of pituitary hormone deficiencies. The dose below which deficiencies do not occur is probably irrelevant to therapeutic irradiation of pituitary and other intracranial neoplasms.

Hypopituitarism following external radiotherapy for pituitary tumours in adults.

The development of anterior pituitary hormone deficiencies has been studied in a group of 165 patients who underwent external radiotherapy for tumours of the pituitary or closely related anatomical sites, and who have been observed for up to 10 years. One hundred and forty had undergone pituitary surgery before radiotherapy. All patients received external radiotherapy by a three-field technique, giving 3750-4250 cGy in 15 or 16 fractions over 20-22 days. A combined test of anterior pituitary function using insulin hypoglycaemia or glucagon stimulation in conjunction with thyrotrophin and gonadotrophin releasing hormone tests and basal estimations of prolactin, thyroid hormones and testosterone or oestradiol was performed before radiotherapy. This was repeated six and 12 months later and subsequently annually. Before radiotherapy, 18 per cent of patients had normal growth hormone secretion, 21 per cent had normal gonadotrophin secretion, 57 per cent had normal corticotrophin reserve and 80 per cent had normal thyrotrophin secretion. Life table analysis demonstrated increasing incidences of all anterior pituitary hormone deficiencies with time: by five years all patients were growth hormone deficient, 91 per cent were gonadotrophin deficient, 77 per cent were corticotrophin deficient and 42 per cent were thyrotrophin deficient. At eight years, respective incidences of deficiencies were 100, 96, 84 and 49 per cent. Radiation-induced hyperprolactinaemia was seen in 73 patients; mean serum prolactin concentration rose from 227 +/- 11 mU/l to a peak of 369 +/- 60 mU/l at two years and subsequently declined towards the basal value. The primary diagnosis, patient age, sex, irradiated tissue volume and previous surgery were examined as variables that might influence the rate of development of anterior pituitary hormone deficiencies, but none of these factors had a significant effect. The radiation induced hyperprolactinaemia was however more marked in female patients. Although anterior pituitary hormone deficiencies most commonly developed in the order growth hormone, gonadotrophin, corticotrophin, thyrotrophin (61 per cent of patients), other sequences were evident. Most notably corticotrophin deficiency occurred before gonadotrophin deficiency. There is a high incidence of anterior pituitary hormone deficiencies in patients treated surgically for pituitary tumours and the incidence increases after external radiotherapy. Deficiencies may occur in an unpredictable sequence and endocrine testing is recommended on an annual basis.

Treatment of Cushing's disease with low dose radiation therapy.

Nineteen patients with Cushing's disease were treated with low dose external pituitary irradiation (20 Gy (2000 rad) in eight fractions over 10 days). While awaiting the effects of pituitary irradiation all patients were treated with metyrapone. Seven patients had a complete remission of their disease within six to 12 months of irradiation. They did not require any further treatment and were followed up for a mean of three and a half (range one to eight) years. Another patient had a complete remission after a second course of pituitary irradiation. A further two patients showed a significant biochemical improvement after irradiation, although they were not rendered eucorticoid. There were no complications after this dose of irradiation. These results compare favourably with those reported after pituitary irradiation at conventional doses (40-50 Gy (4000-5000 rad) over four or five weeks) but were not associated with any complications. It is therefore recommended that low dose external pituitary irradiation be used as definitive first line treatment for Cushing's disease.

Discordant serum alpha-subunit and FSH concentrations in a woman with a pituitary tumour.

We have studied a women who presented at the age of 51 with a large FSH and alpha-subunit producing pituitary adenoma. Following insertion of ventriculo-peritoneal shunts and external pituitary irradiation there was no change in the elevated serum concentrations of FSH, and alpha-subunit over a four year period although she developed both ACTH and TSH deficiency. Various drugs, however, did alter the FSH and alpha-subunit concentrations and these changes suggest possible mechanisms controlling FSH secretion. Ethinyloestradiol 0.03 mg daily for three weeks suppressed serum FSH to 77% of the basal level (240 +/- 35 i.u./l to 184 +/- 20 i.u./l) but alpha-subunit rose to 130% of basal level (281 +/- 50 ng/ml to 366 +/- 40 ng/ml). On ethinyloestradiol 0.1 mg daily, FSH suppressed to 17% of basal (40 +/- 11 i.u./l) with no change in alpha-subunit concentration, while on 0.2 mg daily suppression of FSH was similar but alpha-subunit fell to 59% of basal (190 +/- 28 ng/ml). Dexamethasone, 3 mg daily for one week reduced FSH to 53% of the initial concentration and alpha-subunit to 74% while bromocriptine 7.5 mg daily for three months, reduced FSH to 39% and alpha-subunit to 66% of basal. Neither thyroxine, 0.2 mg daily for four weeks, nor an LHRH analogue, (Buserelin, Hoechst) 200 micrograms, three times daily for three months elicited any effect. Chromatography on Sephadex G100 showed that serum FSH and alpha-subunit both had Kav values somewhat lower than those of their standard counterparts (FSH, 0.20 vs 0.25; alpha-subunit 0.35 vs 0.45).(ABSTRACT TRUNCATED AT 250 WORDS)

On the sensitisation of skin radionecrosis in mice by misonidazole at low doses.

The sensitisation by misonidazole of tail radionecrosis in mice has been assessed using single doses from 0.01 to 1 mg g-1 body weight, for tails in three different states of oxygenation affecting sensitivity. The levels of sensitisation after different injected doses of misonidazole could be described reasonably well by the Alper -Howard-Flanders relationship, originally applied to the sensitisation of cells by oxygen, and hence the relationship could be used for interpolation. With clamped tails gassed with nitrogen at room temperature, 21-25 degrees C, the injected dose giving half the maximum sensitisation (defined as K inj ) was about 0.12-0.17 mg g-1 (0.6-0.8 mM). Unclamped tails in air demonstrated a value for K inj of about 0.14 mg g-1, indicating that the background level of oxygen and the injected misonidazole were not additive regarding sensitisation. With clamped tails gassed with nitrogen warmed to 37 degrees C (near body-core temperature) the sensitivity was slightly increased compared with clamped tails at 21-25 degrees C, and the additional increase in sensitivity following injections of misonidazole ( K inj of about 0.22 mg g-1) was less than at 21-25 degrees. With tails in air at 37 degrees C the increase in sensitivity following misonidazole was much more marked ( K inj of about 0.05 mg g-1) than expected. When eight "daily" fractions were given using 0.67 mg g-1 misonidazole and with the target cells well oxygenated at 37 degrees C (effective OER of about 2.0), the amount of sensitisation was less than for single doses, but it was similar (i.e. dose-modifying) for radiation doses per fraction between 2.6 and 6.3 Gy. At a dose of 0.1 mg g-1, giving a serum level corresponding to about the maximum tolerable in humans, the dose reduction factor would be only about 1.03 which corresponds roughly to a doubling in the tail necrosis rate from 5% to 10%. With future less neurotoxic drugs, higher serum levels may be expected to be tolerated and hence the dose reduction factor could be greater. This aspect, applicable to some but not all tissues tested in mice, should not be neglected in the design of future clinical trials with hypoxic-cell radiosensitisers .

General reproduction, perinatal-postnatal, and teratology studies of nitrofurantoin macrocrystals in rats and rabbits.

Urinary tract infections in pregnant women are common and require prompt, effective treatment. Currently, no antibacterial agents have received regulatory approbation for use without restriction during pregnancy. The choice of a drug for use in pregnant women requires careful examination of its possible maternal and fetal toxicity as well as its teratogenic potential. We conducted studies to determine the effects of nitrofurantoin macrocrystals (Macrodantin, Norwich Eaton Pharmaceuticals, Inc.), a synthetic antibacterial, on reproductive capability, fetal development, and neonatal survival in the rat and the rabbit. Doses of 10.0, 20.0, and 30.0 mg/kg.d, approximately 2, 4, and 6 times the daily human therapeutic dose, were administered orally in a methylcellulose suspension to rats and rabbits in general reproduction, perinatal-postnatal, and teratology studies. Safety was assessed by evaluating reproductive capability, fertility, gestation period, fetal and neonatal death, litter size and viability, birth weight and postnatal growth, and malformations. Under the conditions of these studies, treatment with nitrofurantoin macrocrystals in rats and rabbits before or during pregnancy or during lactation caused no adverse effects in the mother, fetus, or neonate. These findings support the premise that nitrofurantoin macrocrystals constitute a safe treatment for urinary tract infection during pregnancy.

External pituitary irradiation as a cause of TRH deficiency in patients with pituitary adenomas.

The influence of external pituitary irradiation (XRT) on thyrotroph function and PRL secretion was studied in twenty-five patients with pituitary adenomas, of whom eight had acromegaly. Twenty-one patients had undergone subtotal operative removal of their adenomas 8-190 weeks (median 12 weeks) before XRT. Following irradiation there was a significant reduction in peak serum TSH levels in response to i.v. TRH (P less than 0.05, compared with before XRT). Peak TSH levels returned to normal at 3 months. Similarly a transient reduction in TRH-stimulated beta-TSH release was observed. Serum T3 and T4 concentrations also fell after XRT, the levels at 3 months being significantly lower than control values (P less than 0.02), though no difference was seen at 6 and 12 months. A delayed (hypothalamic) serum TSH response to TRH (60 greater than 20-min level) developed at 6 months. In contrast, PRL concentrations (basal and TRH stimulated) were not altered during the 12 months following XRT. These findings demonstrate that thyrotroph function can be transiently impaired following external pituitary irradiation. None of the patients studied required T4 replacement therapy. The development of a delayed TSH response to i.v. TRH may indicate endogenous TRH deficiency. It was not associated with supra-sellar tumour enlargement in our patients and may be due to hypothalamic damage by irradiation.

Glycoprotein hormone alpha subunit secretion by pituitary adenomas: influence of external irradiation.

In ninety-nine patients with pituitary adenomas, forty-six with acromegaly, the serum level of the glycoprotein hormone alpha subunit was elevated in eighteen cases. Thirteen of these were acromegalic and one had an FSH-producing tumour. Alpha levels varied little during the day, from one day to the next and over a 6 month period. In twenty-five patients with a variety of other hypothalamic-pituitary disorders examined, one patient with a craniopharyngioma had a mildly elevated alpha level. External pituitary irradiation was followed by an acute and often transient fall in alpha level in several of these patients. Of the fifty-four patients with pituitary adenomas who had received external irradiation before testing, only five had elevated alpha subunit levels compared with thirteen patients of the forty-five who had not been irradiated. This difference in incidence of elevated alpha level was statistically significant (P less than 0.025). We conclude that external irradiation may reduce alpha subunit level chronically in many patients with pituitary adenoma.