Characterization of a maize beta-amylase cDNA clone and its expression during seed germination

A maize (Zea mays L.) cDNA clone (pZMB2) encoding beta-amylase was isolated from a cDNA library prepared from the aleurone RNA of germinating kernels. The cDNA encodes a predicted product of 488 amino acids with significant similarity to known beta-amylases from barley (Hordeum vulgare), rye (Secale cereale), and rice (Oryza sativa). Glycine-rich repeats found in the carboxyl terminus of the endosperm-specific beta-amylase of barley and rye are absent from the maize gene product. The N-terminal sequence of the first 20 amino acids of a beta-amylase peptide derived from purified protein is identical to the 5th through 24th amino acids of the predicted cDNA product, indicating the absence of a conventional signal peptide in the maize protein. Recombinant inbred mapping data indicate that the cDNA clone is single-copy gene that maps to chromosome 7L at position 83 centimorgans. Northern blot analysis and in vitro translation-immunoprecipitation data indicate that the maize beta-amylase is synthesized de novo in the aleurone cells but not in the scutellum during seed germination.

Prevalence of lens opacities in the Barbados Eye Study

OBJECTIVE

To present population-based data on type and extent of age-related lens opacities in the predominantly black population of the Barbados Eye Study.

DESIGN

Prevalence study.

SETTING AND PARTICIPANTS

The Barbados Eye Study included 4709 participants (84% of those eligible), who were identified from a random sample of Barbadian-born citizens aged 40 to 84 years.

DATA COLLECTION

Lens gradings at the slit lamp, obtained with the use of the Lens Opacities Classification System II.

MAIN OUTCOME MEASURE

Prevalence of posterior subcapsular, nuclear, and cortical opacities (defined as a grade > or = 2 in either eye), as well as prevalence of any lens changes (including history of previous cataract surgery and/or cataract too advanced to grade).

RESULTS

Overall, 41% of the Barbados Eye Study population had any lens changes, including 3% with aphakia or an intraocular lens. Among the population of African descent, cortical opacities (34%) were most prevalent, followed by nuclear (19%) and posterior subcapsular (4%) opacities. Prevalence of all opacity types increased with age (P < .001). Cortical and nuclear opacities were more frequent in women than men. When prevalence of a single kind of opacity was considered, 21% of participants had cortical only, 6% had nuclear only, and 0.4% had posterior subcapsular only; 13% had mixed opacities. Visual acuity loss to worse than 20/40 in the more affected eye was present in 48%, 26%, and 18% of nuclear only, posterior subcapsular only, and cortical only types, respectively, and in 53% of mixed opacities.

CONCLUSIONS

The Barbados Eye Study provides the first prevalence data on different types of lens opacities in a large, predominantly black population. Whereas nuclear opacities are most common in white populations, cortical opacities were the most frequent type in the Barbados Eye Study, a finding of possible etiologic relevance. Other results highlight a higher frequency of opacities in women than men and a high prevalence of visual acuity loss in affected eyes.

Establishment of stable cell lines expressing potentially toxic proteins by tetracycline-regulated and epitope-tagging methods

A tetracycline-regulated expression system is combined with the FLAG-epitope tagging method for conditional expression of potentially toxic proteins in mammalian cells. This strategy allows a controlled expression of exogenous gene products and also provides a unique way of protein purification. Two mammalian expression plasmids containing the FLAG sequence and flanking multiple cloning sites were created for conditional protein expression. The cDNAs encoding human basal transcription factors TBP, TAFII55 and the p62 subunit of TFIIH were individually cloned into these vectors and introduced into a HeLa-derived cell line that constitutively expresses a tetracycline-regulated transactivator (tTA). The established clonal human cell lines express FLAG-tagged basal transcription factors in a manner modulated by the amount of tetracycline in the growth medium. In the absence of tetracycline, tTA binds to the DNA recognition sites of the expression plasmid and induces the expression of tagged proteins. When tetracycline is added back to the growth medium, the induced protein starts to decay. This provides us with an estimation of the in vivo half-lives of TBP and TAFII55, which were assessed to be less than 20 and 6 hours, respectively, in HeLa cells. The level of induced proteins in the absence of tetracycline could be further enhanced by including the antibiotic G418 to presumably boost the production of tTA which in turn activates the expression of tagged proteins.

Birth weight has increased over a generation

The authors examined secular trends in birth weight for a geographically defined population over 40 years, controlling for migration effects. The study was an analysis first of all Illinois births between 1950 and 1990 and second of a subset of births for which two succeeding generations were born in the state. For the latter analysis, the authors created a transgenerational birth file by linking infant birth records to the birth records of their parents. Shifts toward bigger babies were observed in both data sets. For black births, the shift was larger in the transgenerational file; but for white infants, similar magnitude shifts were observed in the two files. In both analyses, there were larger birth weight shifts for whites than for blacks. Mean birth weight increases within families ranged from 33 g (black male infants compared with their fathers) to 74 g (white female infants and their mothers). The rate of births at very low birth weight (< 1,500 g) decreased by 6% in the white population but increased by 56% in blacks. Results presented in this study demonstrate that even when migratory effects are eliminated, a secular increase in birth weight is observed. Moreover, the left tall of the birth weight distribution does not always follow the same temporal trend observed for the mode.

Potentiation of IPSCs by nitric oxide in immature rat sympathetic preganglionic neurones in vitro

1. Whole-cell patch-clamp recording techniques were applied to sympathetic preganglionic neurones (SPNs), the majority of which contain neuronal nitric oxide synthase (NOS), in transverse thoracolumbar spinal cord slices from 8- to 12-day-old rats, and the role of nitric oxide (NO) in modulating the inhibitory postsynaptic current (IPSC) evoked by focal stimulation was examined. 2. Superfusing the slices with the NO precursor L-arginine (L-Arg, 300 microM) and the NO donor sodium nitroprusside (SNP, 100 microM) potentiated IPSCs from several minutes to more than 1 h; the increase was prevented by pretreating the slices with bovine haemoglobin (100 microM), the nitric oxide synthase inhibitor N omega-nor-L-arginine (NO-Arg, 100 microM) or the soluble guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, 1 microM). Haemoglobin, NO-Arg and ODQ slightly reduced the IPSCs evoked in some of the SPNs. 3. Superfusion of the slices with N2,2'-O-dibutyrylguanosine 3',5'-cyclic monophosphate (dbcGMP, 300 microM) in the presence of the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX, 750 microM) reversibly increased the IPSCs as well. 4. While enhancing the IPSCs, L-Arg or SNP had no significant effects on outward currents induced by pressure application of the putative inhibitory transmitter glycine in the same cells. 5. A train of suprathreshold depolarizing current pulses (30 Hz for 10 s) injected into the recording SPNs caused, after a delay of several minutes, a long-lasting increase of IPSCs; this effect was nullified by superfusing the slices with haemoglobin or NO-Arg. 6. The result suggests that NO released endogenously from SPNs may act as a retrograde messenger molecule to enhance the release of glycine or a related substance, possibly via a cGMP-dependent mechanism.

Subacute neurotoxicity induced in mice by potent organophosphorus neuropathy target esterase inhibitors

The mouse is considered to be insensitive and the hen sensitive to clinical expression of organophosphorus-induced delayed neuropathy (OPIDN) which is associated with inhibition of neuropathy target esterase (NTE). This species difference is reevaluated with two optimized inhibitors of hen brain NTE by examining them for potential neurotoxic effects in mice. 2-Octyl-4H-1,3,2-benzodioxaphosphorin 2-oxide (OBDPO) and ethyl octylphosphonofluoridate (EOPF) inhibit mouse brain NTE in vitro by 50% at 0.12 and 0.02 nM and induce neurotoxic signs in mice at 10 and 5 mg/kg, respectively. The action of these compounds in both l- and 6-month-old mice, sometimes after early transient cholinergic signs, involves ataxia, paralysis, and death in 1 to 3 days and is accordingly referred to as subacute neurotoxicity. The neurotoxic signs are associated with brain edema and severe vacuolation in the grey matter of the brain and spinal cord, particularly the neuropile. Subacute neurotoxic signs are always associated with at least 80% inhibition of brain NTE activity 16-24 hr after treatment. Acetylcholinesterase and butyrylcholinesterase are much less sensitive than NTE to inhibition by OBDPO and EOPF both in vitro and in vivo. Selected carbamates, thiocarbamates, phosphinates, and sulfanyl fluorides are prophylactic agents and dipentyl 2,2-dichlorovinyl phosphate is a promoter for OBDPO-induced subacute neurotoxicity. Although this type of neurotoxicity in mice is similar to OPIDN in the correlation with NTE inhibition and the prophylactic action of reversible NTE inhibitors, it differs from OPIDN in the delay time prior to onset, the sensitivity of both young and old animals, and the high incidence of fatality. A full neuropathological study is desirable to further characterize this subacute neurotoxicity.

Maturation of hepatic desulfation activity in developing rats

The present study was carried out to further characterize the maturation of desulfation activity in developing rats. High levels of 3,3',5-triiodothyronine sulfate (T3S) were found in rat fetal serum whereas 3,3',5-triiodothyronine (T3) levels were low. The ratio of T3S/T3. was dramatically reversed in the rat maternal circulation. Maternal rats had higher desulfation activity than did near-term fetuses. Desulfation of T3S to T3 by microsomes of fetal and maternal livers were studied by incubating microsomes with T3S as a substrate. Desulfated T3 was measured by radioimmunoassay. The Km and Vmax values for desulfation of T3S to T3 by hepatic microsomes in different age groups were compared. Little desulfation activity was found in hepatic microsomal preparations from fetal rats compared with newborn rats. There was a trend of increasing desulfation activity in rats after birth until 1 month of age, although this was not significant. A surge of desulfating activity was observed between the 1- and 2-month old groups. The K(m) values for T3S desulfation activity were similar in all age groups. The Vmax values for the T3S to T3 desulfation activity progressively increased after birth until 2 months of age. The Vmax of the latter group, however, was comparable to that of the maternal group. These results suggest that the maturation of desulfation activity in the microsomal preparations from rat livers is completed by 2 months of age and is mainly due to increased enzyme capacity. Sulfation-desulfation of T3 may play a role in the thyroid hormone regulation of developing mammals.

Open-angle glaucoma and ocular hypertension: the Long Island Glaucoma Case-control Study

This case-control study evaluated risk factors for open-angle glaucoma (OAG) and high intraocular pressure (IOP), including systemic hypertension and its treatment, other systemic factors, familial, and demographic variables. The three study groups were based on masked ophthalmologic gradings of visual fields and fundus photographs, as well as tonometry. The OAG group (n = 122) had OAG field defects, IOP > 21 mmHG, and cup-disc ratios > or = 0.5 and/or evidence of glaucoma disc damage. The ocular hypertensives (n = 108) had no field defects, IOP > 21 mmHg and normal discs. The controls (n = 190) had no field defects, IOP < 21 mmHg and normal discs. The data collection protocol included a standardized interview and measurements. Medical history was confirmed by contacting the primary care physicians (89% response from physicians). Study groups were compared by polychotomous logistic regression analyses. Men were more likely to have OAG and less likely to have ocular hypertension. Systemic hypertension was more frequent in ocular hypertensives (Odds Ratio = 2.36); high diastolic pressure was associated with OAG and ocular hypertension (OR = 2.13 and 2.21, respectively). Treatment for systemic hypertension was unrelated to OAG risk. Low perfusion pressures (blood pressure-IOP differences) were strongly associated with OAG and ocular hypertension, a finding that could be due to the high IOP in these groups. A family history of glaucoma was more frequent in OAG (OR = 3.08) and ocular hypertension (OR = 2.38) than in controls. Alcohol consumption was related to ocular hypertension (OR = 2.32). No other associations were significant. The results confirm an association of blood pressure with intraocular pressure. Since the OAG and ocular hypertensive groups had similar blood pressure results, an independent effect of blood pressure on OAG was not substantiated.

Incidence and progression of nuclear opacities in the Longitudinal Study of Cataract

PURPOSE

To estimate incidence and progression rates of nuclear opacities in the Longitudinal Study of Cataract, an epidemiologic study of the natural history of all types of lens opacities.

METHODS

The Lens Opacities Classification System III was used to assess longitudinal changes between baseline and follow-up lens photographs for the 764 Longitudinal Study of Cataract participants. Baseline data, collected until December 1988 as part of a case-control study, included color slit, retroillumination, and Scheimpflug photographs. The same data were collected by the longitudinal Study of Cataract at four subsequent visits at yearly intervals.

RESULTS

Among patients free of nuclear opacities at baseline, the incidence of new opacities was 6% after 2 years and 8% after 5 years of follow-up. The progression of pre-existing nuclear opacities was much higher. After 2 years, nuclear opacities had progressed in more than one third of the patients with pre-existing opacities; after 5 years, almost half had progressed. Older age was significantly related to higher incidence of new nuclear opacities, but not to progression of pre-existing opacities. Patients with other opacity types had higher nuclear incidence and progression rates.

CONCLUSIONS

In this clinic-based, older-patient population, new nuclear opacities developed in less than one tenth of the patients after 5 years of follow-up. In contrast, almost one half of the patients with pre-existing opacities had worsened after 5 years. These estimated rates can be used to plan intervention or other studies of nuclear changes in similar populations.

Serum iodothyronine concentrations in intestinally decontaminated rats treated with a 5'-deiodinase type I inhibitor 6-anilino-2-thiouracil

Enteric bacteria have been postulated to have a role in thyroid economy by promoting the hydrolysis of thyroid hormone conjugates of biliary origin, thus permitting the absorption and recycling of thyroxine (T4) and triiodothyronine (T3). An enterohepatic circulation of T3 might be more pronounced under conditions in which type I iodothyronine deiodinase activity (5'D-I) is inhibited, because this augments the accumulation of T3 sulfate conjugates in bile. This potential of increased gut reabsorption of T3 might explain, at least in part, the failure of serum T3 values to decrease appreciably when marked reductions in peripheral 5'D-I activity are induced by selenium deficiency or 6-anilino-2-thiouracil (ATU) administration. Thus, studies were performed to determine the effect of intestinal decontamination, in the absence and in the presence of 5'D-I inhibition, on plasma T4 and T3 concentrations. Groups of adult male rats received either enteric antibiotics or no antibiotics for 12 days and then, in half of the rats in each group, treatment for 10 days with ATU, a 5'D-I inhibitor that does not affect thyroid hormone synthesis. The activity of intestinal arylsulfatase and arylsulfotransferase, enzymes that catalyze hydrolysis of thyroid hormone conjugates, was reduced markedly by approximately 87% in rats that received antibiotics, regardless of whether or not they also received ATU. The ATU treatment markedly inhibited liver 5'D-I activity in antibiotic-treated as well as in non-antibiotic-treated rats (control = 399 +/- 32 U/mg protein (mean +/- SEM); ATU = 152 +/- 17: antibiotics = 351 +/- 29; antibiotics + ATU = 130 +/- 10; p < 0.01) and significantly increased plasma T4 and T3 sulfate (T4S, T3S) concentrations (control: T4S = 2.8 +/- 0.4 and T3S = 6.7 +/- 1.3 ng/dl; ATU: T4S = 6.2 +/- 1.4 and T3S = 10.6 +/- 2.1 ng/dl; antibiotics: T4S = 1.8 +/- 0.2 and T3S = 3.6 +/- 1.0 ng/dl; antibiotics + ATU: T4S = 6.8 +/- 0.7 and T3S = 9.7 +/- 1.8 ng/dl; p < 0.05). The ATU treatment was associated with a significant increase in plasma T4 and rT3 concentrations but did not affect plasma T3 concentrations, and intestinal decontamination did not alter these ATU-associated effects on circulating thyroid hormones. These results suggest that anaerobic enteric bacteria in the rat do not have an important role in recycling of thyroid hormones, either under normal conditions or in circumstances where 5'D-I activity is markedly reduced, and that increased gut absorption of T3 from T3S cannot explain the near-normal serum T3 values found when peripheral 5'D-I activity is markedly decreased.

Increased urinary excretion of sulfated 3,3',5-triiodothyronine in patients with nodular goiters receiving suppressive thyroxine therapy

Increased serum 3,3',5-triiodothyronine sulfate (T3S) levels have been detected in various pathophysiologic states. However, little is known about T3S concentrations in other biological fluids. By employing a highly sensitive, specific, and reproducible radioimmunoassay (RIA), we measured T3S in the serum and urine of 20 premenopausal women with benign nodular goiters before and after administration of thyroxine for 6 months (T4; 3.2 micrograms/kg/day). Serum T3 concentrations did not change significantly after treatment (2.0 vs. 1.7 nmol/L; p > 0.05). However, the mean serum T4 and free T4 concentrations were significantly higher after treatment (138 vs. 88 nmol/L and 28 vs. 17 pmol/L; p < 0.01, respectively). Serum thyroid stimulating hormone (TSH) levels were significantly reduced after T4 treatment (0.13 vs. 0.66 mU/L, p < 0.01) and the serum levels of T3S were significantly increased after treatment (82 vs. 45 pmol/L; p < 0.01). A good correlation was observed between increased serum T3S and T4 concentrations (r = 0.66; p < 0.001). The sulfoconjugate of T3 was significantly increased in creatinine-corrected urine after treatment (606 vs. 253 pmol/umol Cr.; p < 0.01). There was a significant correlation between increased creatinine-corrected urine T3S and increased serum free T4 (r = 0.65; p < 0.001). In summary, significant increases in serum and urine T3S levels were noted in T4-treated patients with subnormal serum TSH and borderline elevated T4. We thus conclude that the sulfation pathway may play a role in the homeostasis of thyroid hormone metabolism in T4-treated subjects with relative hyperthyroxinemia. In addition, the creatinine-corrected urine concentrations of T3S may serve as an index for the evaluation of T4-treated patients with elevated levels of T4.

The effect of exclusive breastfeeding on development and incidence of infection in infants

Of 145 normal fullterm infants studied during the first year after birth, those exclusively breastfed for the first four months differed significantly from those not exclusively breastfed in physical and behavioral development, and resistance to infection. At four months of age, the mean weight of the exclusively breastfed group was higher (p < 0.05). At one year, the exclusively breastfed group showed more advanced. Personal-Social (p = 0.05) and gross Motor development (p < 0.05) on the Denver Developmental Screening TEst, and lesser cumulative incidence of infectious diseases (p < 0.05). This study demonstrated the beneficial effects of breastfeeding on development and resistance to infection in infants.

[Antitumor activity of yungumycin]

Yungumycin, produced by a Streptomyces strain which was isolated from a soil sample collected in Guanping Nature Conservation Zone, Yunnan Province, China, has been verified to be identical with gougerotin. Determined by clonogenic assay, the IC50 of yungumycin to KB cells was found to be 1 microgram.ml-1. By spermatogonial assay, the activity of yungumycin was very close to that of 5-FU and MTX. Administered by i.p. route, yungumycin showed moderate inhibition against colon carcinoma 26 in mice. However, yungumycin by oral administration exerted highly inhibitory effects on both colon carcinoma 26 and sarcoma 180 (solid tumor) in mice and the inhibition rates reached 85% and 83%, respectively, at tolerable dose. Compared at equitoxic dose of 1/6 LD50, the inhibitory effect of yungumycin (15 mg.kg-1) on sarcoma 180 was similar to that of 5-FU (40 mg.kg-1), showing 72% and 70% tumor inhibition, respectively. Initially, gougerotin was reported as an antibacterial antibiotic without mentioning its antitumor activity. The present studies demonstrate that yungumycin (gougerotin), by oral administration, may be useful in cancer chemotherapy.

Calcium-activated release of nitric oxide potentiates excitatory synaptic potentials in immature rat sympathetic preganglionic neurons

1. Whole cell patch recordings were made from sympathetic preganglionic neurons (SPNs), the majority of which contain brain nitric oxide synthase (bNOS), in transverse spinal cord slices of 12- to 16-day-old rats. 2. Repetitive discharge of SPNs induced by a train of depolarizing current pulses (40 Hz. 10 s) was followed by a long-lasting increase (140 +/- 22%, mean +/- SD) of the amplitude of excitatory postsynaptic potentials (EPSPs) evoked by stimulation of lateral funiculus in 50 of 75 SPNs. 3. In slices pretreated with the nitric oxide synthase inhibitors, NG-monomethyl-L-arginine (L-NMA: 100 microM) or Nw-nitro-L-arginine (L-NARG; 30 microM) or with bovine hemoglobin (100 microM), repetitive discharge of SPNs was not followed by a significant increase of EPSPs. 4. Superfusing the slices with L-arginine (L-Arg, 300 microM) but not D-Arg reversibly increased the EPSPs by an average of 140 +/- 19%. 5. Inclusion of the Ca2+ chelator 1.2-bis(2-aminophenoxy)- ethane-N,N,N',N'-tetraacetic acid (BAPTA, 1 mM) in the patch electrodes resulted in no significant increase of EPSPs after repetitive discharge in all cells studied. 6. It is concluded that during repetitive discharge of SPNs, Ca2+ influx via voltage-gated channels activates bNOS, resulting in a release of nitric oxide and potentiation of EPSPs.

Ethyl octylphosphonofluoridate and analogs: optimized inhibitors of neuropathy target esterase

The relation between organophosphorus-induced delayed neuropathy (OPIDN) and brain neuropathy target esterase (NTE) inhibition is further examined in hens by structure-activity studies leading to the most potent in vitro NTE inhibitors known, which are then examined for their neuropathic effects in vivo in hens. The principal compounds studied are alkyl alkylphosphonofluoridates and dialkyl phosphorofluoridates. Potencies that exceed those of any previous inhibitors under the standard in vitro NTE assay condition are achieved with alkyl octylphosphonofluoridates (ethyl, isopropyl, 2-chloroethyl, 2-bromoethyl, 2-iodoethyl, and 3-iodopropyl), 2-iodoethyl hexylphosphonofluoridate, and dialkyl phosphorofluoridates [ethyl, nonyl; di(2-iodoethyl); di(3-iodopropyl); dipentyl]. The concentration for 50% NTE inhibition (I50) of these compounds is 0.04-0.14 nM. Thirty-eight less active analogs including aryl phosphonates and aryl phosphates give I50s of 0.27-4730 nM. For highest potency the summation of length of the alkyl and alkoxy groups on phosphorus should be 12-16 atoms (carbons, oxygens, and phosphorus) (a terminal iodo substituent in this relationship is equivalent to a propyl group). In general, the phosphonofluoridates and phosphorofluoridates are more active than analogs with leaving groups other than fluorine, i.e., phenoxy, 4-nitrophenoxy, 4-cyanophenoxy, 3,4-dichlorophenoxy, and 4H-1,3,2-benzodioxaphosphorin. Considering the exceptional potencies of ethyl and 2-iodoethyl octylphosphonofluoridates (I50s of 0.04 and 0.09 nM, respectively), it is not surprising that at ip doses of 10-30 mg/kg they inhibit brain NTE by 82-97% 48 h after treatment. However, unexpectedly, only the ethyl but not the 2-iodoethyl compound induces OPIDN, possibly associated with the greater ease of aging for NTE inhibited with the ethyl than the 2-iodoethyl compound (as observed in vitro both spontaneously and on induction by potassium fluoride). The high potency of ethyl octylphosphonofluoridate and several analogs as NTE inhibitors suggests that they are useful probes in determining the toxicological features of this secondary lesion for organophosphorus poisoning.

Plasma catecholamine and ventilatory responses to cycling after propranolol treatment

The purpose of the present study was to examine the relationship between minute ventilation (VE) and plasma concentrations of epinephrine (EPI) and norepinephrine (NE) during incremental cycling (20 W.2 min-1) performed under conditions of beta-adrenergic blockade (80 mg of propranolol) and placebo in six untrained male subjects. No significant differences existed between treatments in O2 uptake, CO2 output, blood lactate, pH, or VE during the submaximal work stages of incremental exercise common to both treatments (20 - 220 W). During exercise with beta-blockade, EPI, and NE concentrations were both significantly elevated compared with control levels at every submaximal work stage. Significant positive correlations between VE and plasma levels of EPI and NE were found during both beta-blockade (r = 0.98 and 1.00) and control conditions (r = 0.98 and 0.96). Although the high correlations were unchanged during exercise with beta-blockade, the slopes of the regression lines for the VE-EPI and the VE-NE relationships were both significantly reduced compared with control conditions. Beta-blockade resulted in elevated plasma levels of both EPI and NE compared with control conditions without causing a change in exercise VE. These findings suggest that catecholamines may not be important substances in regulating breathing during exercise.

Antenatal diagnosis and treatment of fetal goitrous hypothyroidism: case report and review of the literature

The recognition and treatment of fetal hypothyroidism are believed to be important to optimize growth and intellectual development in affected fetuses. We present a case of fetal goiter diagnosed by ultrasonography in the second trimester of pregnancy. Cordocentesis performed at 28 weeks confirmed the presence of fetal hypothyroidism. Fetal therapy was performed with weekly intra-amniotic injections of thyroxine from 29 to 36 weeks. A repeat cordocentesis at 35 weeks showed normalization of fetal thyroid function. The fetal goiter decreased rapidly in size following fetal treatment. Amniotic fluid levels of thyroid stimulating hormone (TSH) and free thyroxine were obtained with each amniocentesis. Sulfated iodothyronine concentrations in maternal blood were obtained before and after fetal thyroxine treatment. This report discusses the role of amniotic fluid levels of TSH and free thyroxine and maternal levels of sulfated iodothyronine in the diagnosis and management of fetal hypothyroidism. A review of the English literature is presented.

Biochemical factors in the lens opacities. Case-control study. The Lens Opacities Case-Control Study Group

OBJECTIVE

To evaluate associations with biochemical indicators of nutritional and other risk factors in the Lens Opacities Case-Control Study.

DESIGN

Case-control study.

SETTING AND PARTICIPANTS

The Lens Opacities Case-Control Study determined risk factors for cortical, nuclear, and posterior subcapsular opacities among 1380 participants aged 40 to 79 years.

DATA COLLECTION

Vitamin E, selenium, and biochemistry profile determinations were performed on all patients; red blood cell enzymes and amino acids were measured in systematic samples of about 25% of the Lens Opacities Case-Control Study population.

OUTCOME

Laboratory test values in cases and controls were compared and expressed as odds ratios and 95% confidence intervals.

RESULTS

In polychotomous logistic regression analyses controlling for age and sex, the risk of opacities was reduced to less than one half in persons with higher levels of vitamin E (odds ratio, 0.44 for nuclear opacities), albumin-globulin ratio (odds ratio, 0.41 for mixed opacities), or iron (odds ratio, 0.43 for cortical opacities); higher uric acid levels increased risk (odds ratio, 1.74 for mixed opacities). Persons with opacities were twice as likely to have high glutathione reductase activity (with flavin adenine dinucleotide), which suggests low riboflavin status (odds ratio, 2.13). Most odds ratios for amino acids were under unity and were significantly decreased for glycine (0.36) and aspartic acid (0.31).

CONCLUSIONS

Lens opacities were associated with lower levels of riboflavin, vitamin E, iron, and protein nutritional status. Higher levels of uric acid increased risk of mixed opacities. The findings for riboflavin, vitamin E, iron, and uric acid are compatible with the dietary intake and medical history results of the Lens Opacities Case-Control Study.

The use of fluorophore-containing spin traps as potential probes to localize free radicals in cells with fluorescence imaging methods

Central to the study of free radical processes is the ability to identify and localize their cellular site of formation. Under the best of experimental conditions, spin trapping/ESR spectroscopy can only characterize intracellular production of specific free radicals and confocal microscopy can only localize the site of their formation. In this article, we report on the development of a fluorophore-containing nitrone, alpha-[4-[5-((2-carboxy)phenyl)-5-hydroxy-4-oxo-3-phenyl)-2-pyrrolin+ -1-yl]phenyl]-N-(tert-butyl)nitrone sodium salt (4). This nitrone (4) reacts with alpha-hydroxyethyl radical with a second order rate constant of 1.7 x 10(5) M-1 s-1 to give a characteristic ESR spectrum. However, we were unable to decrease the fluorescence emission, due in part to the small concentration of nitroxide generated from the reaction of alpha-hydroxyethyl radical with nitrone (4). Using the fluorophore-containing nitroxide (7) as a model, we found that only 12% of the nitroxide needs to be reduced to give an almost 400% increase in the fluorescent emission of (7). Our findings suggest new approaches to the development of various fluorophore-containing nitrones that can both characterize specific free radicals and localize their site of intracellular formation.

Risk factors for open-angle glaucoma. The Barbados Eye Study

OBJECTIVE

To evaluate risk factors for open-angle glaucoma among black participants in the Barbados Eye Study.

DESIGN

Population-based study of demographic, medical, ocular, familial, and other factors possibly related to open-angle glaucoma.

SETTING AND PARTICIPANTS

The Barbados Eye Study included 4709 Barbados residents identified by a simple random sample of Barbadian-born citizens, 40 to 84 years of age; participation was 84%. This report is based on the 4314 black participants examined at the study site; 302 (7%) met the Barbados Eye Study criteria for open-angle glaucoma.

DATA COLLECTION

A standardized protocol included applanation tonometry, Humphrey perimetry, fundus photography, blood pressure, anthropometry, and an interview. An ophthalmologic examination was performed for participants who met specific criteria.

MAIN OUTCOME MEASURES

Open-angle glaucoma was defined by the presence of both characteristic visual field defects and optic disc damage. Association of open-angle glaucoma with specific factors was evaluated in logistic regression analyses.

RESULTS

Age, male gender, high intraocular pressure, and family history of open-angle glaucoma were major risk factors; the latter association was stronger in men than women. Lean body mass and cataract history were the only other factors related to open-angle glaucoma. Although hypertension and diabetes were common in Barbados Eye Study participants, they were unrelated to the prevalence of open-angle glaucoma. However, associations were found with low diastolic blood pressure-intraocular pressure differences and low systolic and diastolic blood pressure/intraocular pressure ratios.

CONCLUSIONS

In the Barbados Eye Study black population, persons most likely to have open-angle glaucoma were older men and had a family history of open-angle glaucoma, high intraocular pressure, lean body mass, and cataract history. These results suggest the importance of possible genetic or familial factors in open-angle glaucoma. The role of vascular risk factors is consistent with our finding of low blood pressure to intraocular pressure relationships, but the results could be explained by the high intraocular pressure in open-angle glaucoma.