[Bioreactor-landfill site for leaching solution treatment]

The study utilizes the system combined bioreactor with landfill site to treat leachate. The results show that the system helped the degradation of the organic pollutants in the leachate to be divided into two-phases, the hydrolytic fermentation and acid-production phases mainly occurred in the landfill site, the acidification rate was 40%-50%, the methane-production chiefly occurred in the bioreactor(UASB). It treated the leachate significantly and benefits the collection and utilization of methane gas. Also, the system accelerates the process of degrading municipal solid waste and stabilizing landfill site.

Cloning, molecular characterization, and application of rice epiphytic Bacillus pumilus promoter fragments

To establish a constitutive, high-efficiency expression system for Bacillus pumilus (B.P), we cloned random chromosomal DNA into promoter probe shuttle vector ECE7 and selected for strong promoter activity by chloramphenicol resistance of transformed B. pumilus cells. The nucleotide sequences of nine chromosomal fragments were determined. These DNA fragments range from 300 to 2200 bp in size. The transcription strength of these promoters was estimated by determination of CAT enzyme production in both E. coli and B. pumilus. Transcription start (TS) sites of the cat mRNA were located by primer extension by using total RNA. Preliminary analysis showed that three of the promoter sequences contain -35 and -10 regions like E. coli RNA polymerase sigma70 and B. subtilis sigma43 consensus sequences. One is similar to B. subtilis sigma29, the other two have no conserved sequences like any of the typical consensus sequences of the known sigma factors so far. To estimate the feasibility of the utilization of these promoters, one promoter fragment was subcloned and used to drive the expression of green fluorescent protein (GFP) in B. pumilus cells. This is the first report of B. pumilus promoters randomly cloning from total DNA and molecular analysis of their consensus sequences.

[Electric pulse mediated high efficient gene transfer]

OBJECTIVE

To study gene transfer mediated by electric pulse and optimize the parameters of electric pulse in vivo.

METHODS

10 micrograms plasmid pcD2/LacZ was injected into the quadriceps of 220 Kunming mice. One to two minutes after the DNA injection electric pulse with different parameters was given to the injection site. Three days after, activity of beta-galactosidase was measured, and the expression of Laz2 gene in muscle was determined by histochemical staining.

RESULTS

The activity of beta-galactosidase in electric pulse group (131.6 U/mg +/- 86.6 U/mg protein) was 30 fold higher than that in direct injection group (4.9 U/mg +/- 1.0 U/mg protein) (P < 0.05). Histochemical analysis of muscles injected with a LacZ expression plasmid also showed that in vivo electric pulse increased both the number of positively stained muscle fibers and the density of staining. When the electric pulse was with the parameters of 200 V/cm, 40 ms, 6 pulses and 1HZ, maximal gene expression was achieved.

CONCLUSION

Electric pulse, with optimal parameters, increases gene expression. Electric pulse makes much more gene expression than mere intramuscular DNA injection.

Characterization of extended spectrum beta-lactamase-producing Klebsiella pneumoniae from Beijing, China

Fourteen clinical isolates of Klebsiella pneumoniae with extended-spectrum beta-lactamases (ESBLs) were detected by the double disk synergy test and the Etest ESBL strip. Co-resistances included high MICs for aminoglycosides, fluoroquinolones, tetracyclines, and trimethoprim/sulphamethoxazole. Co-resistance was not observed in five of the 14 strains. These isolates were all genetically distinct as determined by the automated ribotyping method. Isoelectric focusing documented the presence of multiple beta-lactamases (one to four per isolate) with pIs ranging from 5.4 to 8.4. The majority of isolates contained beta-lactamases with pI values of 7.6 and 8.4 consistent with SHV-type ESBLs and an Amp C enzyme, respectively. Emerging ESBL strains in K. pneumoniae compromise the use of agents such as cefotaxime, ceftriaxone, ceftazidime in China; leading to the expansion of quality infection control practices and formulary management programmes to minimize clonal expansion.

A framework for predictive modeling of anatomical deformations

A framework for modeling and predicting anatomical deformations is presented, and tested on simulated images. Although a variety of deformations can be modeled in this framework, emphasis is placed on surgical planning, and particularly on modeling and predicting changes of anatomy between preoperative and intraoperative positions, as well as on deformations induced by tumor growth. Two methods are examined. The first is purely shape-based and utilizes the principal modes of co-variation between anatomy and deformation in order to statistically represent deformability. When a patient's anatomy is available, it is used in conjunction with the statistical model to predict the way in which the anatomy will/can deform. The second method is related, and it uses the statistical model in conjunction with a biomechanical model of anatomical deformation. It examines the principal modes of co-variation between shape and forces, with the latter driving the biomechanical model, and thus predicting deformation. Results are shown on simulated images, demonstrating that systematic deformations, such as those resulting from change in position or from tumor growth, can be estimated very well using these models. Estimation accuracy will depend on the application, and particularly on how systematic a deformation of interest is.

A photic visual cycle of rhodopsin regeneration is dependent on Rgr

During visual excitation, rhodopsin undergoes photoactivation and bleaches to opsin and all-trans-retinal. To regenerate rhodopsin and maintain normal visual sensitivity, the all-trans isomer must be metabolized and reisomerized to produce the chromophore 11-cis-retinal in biochemical steps that constitute the visual cycle and involve the retinal pigment epithelium (RPE; refs. 3-8). A key step in the visual cycle is isomerization of an all-trans retinoid to 11-cis-retinol in the RPE (refs. 9-11). It could be that the retinochrome-like opsins, peropsin, or the retinal G protein-coupled receptor (RGR) opsin12-16 are isomerases in the RPE. In contrast to visual pigments, RGR is bound predominantly to endogenous all-trans-retinal, and irradiation of RGR in vitro results in stereospecific conversion of the bound all-trans isomer to 11-cis-retinal. Here we show that RGR is involved in the formation of 11-cis-retinal in mice and functions in a light-dependent pathway of the rod visual cycle. Mutations in the human gene encoding RGR are associated with retinitis pigmentosa.

An adaptive-focus statistical shape model for segmentation and shape modeling of 3-D brain structures

This paper presents a deformable model for automatically segmenting brain structures from volumetric magnetic resonance (MR) images and obtaining point correspondences, using geometric and statistical information in a hierarchical scheme. Geometric information is embedded into the model via a set of affine-invariant attribute vectors, each of which characterizes the geometric structure around a point of the model from a local to a global scale. The attribute vectors, in conjunction with the deformation mechanism of the model, warranty that the model not only deforms to nearby edges, as is customary in most deformable surface models, but also that it determines point correspondences based on geometric similarity at different scales. The proposed model is adaptive in that it initially focuses on the most reliable structures of interest, and gradually shifts focus to other structures as those become closer to their respective targets and, therefore, more reliable. The proposed techniques have been used to segment boundaries of the ventricles, the caudate nucleus, and the lenticular nucleus from volumetric MR images.

Conjunctival T-cell lymphoma caused by human T-cell lymphotrophic virus infection

PURPOSE

To examine the cause of adult T-cell leukemia/lymphoma.

METHODS

We examined a conjunctival biopsy from a 29-year-old Jamaican man who developed bilateral conjunctival masses. Adult T-cell leukemia/lymphoma was diagnosed using routine histology, immunohistochemistry, electron microscopy, microdissection, and the polymerase chain reaction.

RESULTS

Histopathologic examination revealed a conjunctival lymphoma. Clonality of the T-cell receptor gamma gene and human T-cell lymphotrophic virus gag gene were detected in the malignant cells. The demonstration of the human T-cell lymphotrophic virus gene and the rearrangement of the T-cell receptor gene in this neoplasm provide proof that human T-cell lymphotrophic virus is the cause of this conjunctival T-cell lymphoma.

CONCLUSION

Human T-cell lymphotrophic virus is the cause of adult T-cell leukemia/lymphoma, an aggressive malignancy of CD4+ lymphocytes.

[Detection of Immunoglobulin light chain restriction of mucosa-associated lymphoid tissue type gastric lymphoma using mRNA in situ hybridization]

OBJECTIVE

To evaluate the usefulness of in situ hybridization for Immunoglobulin kappa and lambda light chain mRNA to detect light chain restriction in the diagnosis of primary gastric lymphoma (PGL) of mucosa-associated lymphoid tissue (MALT) type.

METHODS

Twenty-seven cases of PGL of MALT type and 5 cases of gastritis were analyzed using in situ hybridization with fluorescent isothiocyanate (FITC)-labeled oligonucleotide probes for kappa and lambda light chain mRNA. The kappa:lambda ratios of tumor cells, lymphocytes and plasma cells were analyzed to detect light chain restriction and clonal plasma cells.

RESULTS

Light chain restriction was found in 10 of 27 (37%) cases of PGL cases (in 5/9 low grade and 5/18 in high grade). Clonal plasma cells were detected in low grade but not in high-grade cases. No light chain restriction was found in gastritis specimens, the adjacent tissue of tumors or the distant stomach mucosa in lymphoma cases.

CONCLUSIONS

The detection of clonality using mRNA in situ hybridization could be a helpful diagnostic tool for gastric lymphoma. The presence of clonal plasma cells can be a marker of the early lesion of low-grade PGL.

A new mutation in the connexin 32 gene was found in Charcot- Marie-Tooth disease in Chinese patients

OBJECTIVE

To investigate the characteristics of gene mutations of connexin 32 exon 2 in Charcot-Marie-Tooth disease in Chinese patients.

METHODS

Screening for connexin 32 gene mutation was conducted in 6 unrelated CMT1 patients without duplication and 10 unrelated CMT2 patients. Mobility shift of exon 2 was analyzed by SSCP and further confirmed by sequencing. The PCR products were cut by appropriate restricted enzyme in 50 normal controls.

RESULTS

One missense mutation at nucleotides 62(G-->A) was found in a CMT1 patient. 50 normal controls were analyzed by the enzyme HaeIII and no abnormality was found. This proved that the mutation was the cause of disease.

CONCLUSION

This mutation has not been reported previously. A proportion of CMTX patients may exist in the group of CMT1 patients in China.

[Formation of stereocomplexes in atactic poly(methyl methacrylate) studied by FTIR]

The stereocomplexation of atactic poly(methyl methacrylate) (a-PMMA) films after isolated from acetone, benzene, and chloroform solution, respectively, was studied by Fourier transformation infrared (FTIR). The results of spectra showed that the stereocomplex was formed for the films cast from acetone and benzene solutions with the appearance of the characteristic bands for the stereocomplex. The population of trans-trans conformers for the i- and s-sequences increased and the side chain preferred to its energetically optimized conformation during the formation of stereocomplex. The stereocomplexes may be formed by the interactions between the i- and s-sequences in the same molecular chain. During the annealing process the self-aggregation of s-sequences played a role in the aggregation process of stereocomplex, which was a function of annealing temperature and annealing time.

[Study on the effect of aging on the crystallization behavior of syndiotactic polystyrene with in situ FTIR measurement]

The effect of aging on the crystallization of syndiotactic polystyrene (SPS) in glassy state and delta form was investigated with in situ FTIR. It is shown that both aged sample and unaged sample in glassy state show the same crystallization behavior; whereas for samples in delta form, the aged sample crystallized in higher temperature range than the unaged sample does. This result is correlated with the formation of a more stable complex structure which formed by combining the molecules and the solvents even more tightly during the aging process, and hence the release of the solvents occurs at higher temperature to cause the crystal transition from the solvent-included delta form to the solvent-free gamma form. However, the aging process has on effect on the following crystal transition from gamma form to alpha form.

Efficient blue cw Nd:YAG microchip laser with two intracavity frequency doublers

A microchip cavity including a half-monolithic Nd:YAG- KNbO(3) chip and a second KNbO(3) crystal is presented. An output power of up to 30 mW at 473 nm pumped by a single stripe 1-W at 808-nm diode is achieved. The laser can be operated in either single-longitudinal or multilongitudinal mode by rotation of the second frequency-doubling crystal to 0 degrees or 90 degrees from the first one. The cw output noise is less than 2% for both cases.

Effect of SJAMP on human platelet cytoplasmic Ca2+

Using the method of dual-wavelength measurement of platelet [Ca2+]i and Fura-2 as the Ca2+ fluorophore probe, we measured the effect of acidic Mucopolysaccharide from Sticopus Japonicus Selenka (SJAMP) on platelet [Ca2+]i. The results showed that the most significant increase in platelets [Ca2+]i was seen when the concentration of SJAMP was 100 micrograms/ml and the elevation of normal platelet [Ca2+]i was 93.96 +/- 10.24 nmol/L (n = 10). In the presence of extracellular Ca2+ (1 mmol/L), the magnitude of platelet [Ca2+]i response to SJAMP was increased and the [Ca2+]i could reach 116.72 +/- 10.66 nmol/L (n = 10). On the other hand, the magnitude of increased platelet [Ca2+]i induced by SJAMP was smaller and the duration of [Ca2+]i reaching the highest level was longer when compared with other platelet aggregation agents. In the mean time, if platelets were first incubated with cyclooxygenase inhibitor, the rise of [Ca2+]i evoked by SJAMP was inhibited. The results indicated that the mechanism of the rise of [Ca2+]i induced by SJAMP might be dependent upon the generation of prostaglandin endoperoxides and(or) TXA2.

Hepatitis B virus X protein activates expression of IGF-IR and VEGF in hepatocellular carcinoma cells

OBJECTIVE

The expression of insulin-like growth factor I receptor (IGF-IR) and the vascular endothelial growth factor (VEGF) in HepG(2) cells transfected with a hepatitis B virus X (HBx) expression vector was investigated in an attempt to study their possible relationship to the growth of HBx-induced hepatocellular carcinoma (HCC).

METHODS

The eucaryotic expression vector of HBx gene was constructed and introduced into HepG(2) cells. The modified cell HepaG(2)-X was synchronized in a quiescent state by culture of serum deprivation. The IGF-IR and VEGF were analyzed by immunohistochemical and Western blot technique.

RESULTS

The positive rate of IGF-IR expression was 84%A3% in the transfected HBx gene cells, 26%A4% in X(0) control cells. The positive rate of VEGF expressed x cells was 83%A5%, X(0) cells was 28%A6% (P<0.001). The level of IGF-IR and VEGF in serum-starved x modified cells was 1.5 times higher than that of synchronized X(0) modified cells.

CONCLUSION

Since the IGF-IR is a very important growth factor in sustaining the tumor abnormal growth and the VEGF has a crucial role in inducting tumor angiogenesis, our findings indicate that HBx may play an important role in the processes of HCC by activating IGF-IR and VEGF gene expression.

Effect of selenium in combination with Adriamycin or Taxol on several different cancer cells

The anti-neoplastic properties of an Selenium compound were studied in vitro on several tumor cell lines: Breast (MCF-7, MCF-10, SKBR-3, BCAP37), Lung (RH2), Prostate (LNCap and PC-3), Colon (T84, Caco-2), Small Intestine (HCF8), and Liver (HepG2). We also examined additive or synergistic effect of Selenium in combination with standard anti-cancer drugs, Adriamycin (Doxorubicin) and Taxol. The effect of Selenium was assessed by apoptosis; DNA synthesis; growth rate by MTT assay; uptake of amino acid MeAIB by System A; and morphological changes. Our results demonstrate that MCF-7 and SKBR-3 showed increase in apoptosis as measured by DNA fragmentation and increase in "rounded" cells and membrane "blebbing", decrease in MeAIB uptake, and decrease in DNA synthesis. These changes were Selenium dose dependent with optimal inhibition at Selenium concentration between 4 and 40 ng/ml after 72 hrs of treatment. Similar observations were made with RH2, HCF8, Caco-2, and HepG2 cells. In contrast, LNCap, PC-3, and T-84 were not significantly affected by Selenium. However, addition of Adriamycin or Taxol in combination with Selenium caused small but significant inhibition of prostate cancer cells LNCap and PC-3. Addition of chemotherapeutic agents either Taxol or Doxorubicin with Selenium caused further inhibition of MCF-7, SKBR-3, RH2, HCF8, and HepG2 cells. In conclusion, Selenium has a significant anti-neoplastic effect on breast, lung, liver, and small intestinal tumor cells. Supplementation of Selenium enhanced chemotherapeutic effect of Taxol and Doxorubicin in these cells beyond that seen with the chemotherapeutic drugs used alone. These in vitro studies on several cancer cell lines suggest a potential benefit of Selenium-enhancement of anticancer effects other systems, and therefore offer further relevance to clinical trials efforts.

Missense alterations of BRCA1 gene detected in diverse cancer patients

The mutations in the breast cancer susceptible gene BRCA1 are responsible for about 50% of inherited breast cancers and confer increased risk of breast and ovarian cancer to its carriers. BRCA1 gene mutations may also be related with other types of cancers such as prostate cancer and colorectal cancer. The goal of this study was to investigate if BRCA1 mutation could be detected in diverse types of cancers. We used PCR-NIRCA and PCR-SSCP methods for screening the BRCA1 mutation hot regions, exons 2, 5, 11, 16 and 20. The positive samples were sequenced to confirm the nature of the mutations. We have identified a rare sequence variant, A3537G (Ser 1140Gly) in a B cell lymphoma patient and two polymorphisms, A1186G (Gln356Arg) in a brain cancer patient and A3667G (Lys1183Arg) in a germline tumor patient. In conclusion, 3 missense alterations of BRCA1 gene have been identified in cancers other than breast cancer.

Platelet fibrinogen in the patients with idiopathic bleeding platelet disorder

The changes of platelet fibrinogen in patients with obscure cutaneous mucosal bleeding and their relation with disease were evaluated. By using flow cytometry and Western blot, the platelet binding site of fibrinogen and the expression of platelet fibrinogen in 8 cases of obscure bleeding were detected. The results showed that platelet surface binding sites of fibrinogen were 65.38 +/- 3.62 in the resting state and 65.25 +/- 5.78 after activated by adenosine diphosphate, showing no significant difference as compared with control group (P > 0.05). The expression of platelet fibrinogen was obviously decreased in 4 patients and increased in one case as compared with control group. It was concluded that the binding sites of fibrinogen on the platelet surface were normal in the patients with idiopathic bleeding platelet disorder. The abnormal of platelet fibrinogen might be one of hemorrhagic reasons in partial patients.

Mutation analysis of BRCA1 gene in African-American patients with breast cancer

An estimated 7% of all breast cancers and 10% of all ovarian cancers are associated with inherited mutations in BRCA1 and BRCA2 genes. The mutations of a breast cancer-susceptible gene, BRCA1, confers increased risk of breast cancer in young women. Numerous studies have reported specific mutations in the BRCA1 and BRCA2 genes in the white population. However, there are very few studies on African-American and other ethnic minority groups. The goal of this study is to identify whether African-American patients with breast cancer carry some common mutations reported in other ethnic groups and whether they carry some novel mutations. We screened hot-region mutations on exons 2, 5, 11, 16, and 20 of BRCA1 gene in 54 African-American patients with breast cancer by NIRCA and SSCP methods. Our data revealed one novel frameshift mutation (3331 insG) and three missense sequence variants (A3537G, A3667G, and C4009T) on exon 11. Each sequence change was confirmed by automatic DNA sequencing. One rare sequence variant, A3537G, has been revealed in high frequency (3/54). Our data suggested that African-American patients with breast cancer carry some unique BRCA1 gene mutations.

Preparation, purification, and characterization of a reversibly lipidized desmopressin with potentiated anti-diuretic activity

PURPOSE

. To prepare and characterize a reversibly lipidized dipalmitoyl desmopressin (DPP), and to compare its anti-diuretic efficacy and biodistribution with that of unmodified desmopressin (DDAVP).

METHODS

Dithiothreitol (DTT) was used to reduce the intramolecular disulfide bond in DDAVP, and the reduced DDAVP was treated with a thiopyridine-containing disulfide lipidization reagent, Pal-CPD. The product, DPP, was purified by acid precipitation and, subsequently, by size-exclusion chromatography. Reversed-phase HPLC was used to analyze the purity and to evaluate the hydrophobicity of the product. Mass spectrometry was employed to characterize its molecular structure. The biological activity of DPP was demonstrated by the antidiuretic effects in vasopressin-deficient Brattleboro rats. Preliminary pharmacokinetic and biodistribution studies of intravenously injected DDAVP and DPP were carried out in CF-1 mice.

RESULTS

DDAVP was readily reduced by a 2-fold molar excess of DTT at 37 degrees C for 0.5 hr. DPP was formed by the reaction of reduced DDAVP with Pal-CPD. Each DPP molecule contains two palmitic acid moieties, which link to the peptide via two disulfide bonds. After acid precipitation and size-exclusion chromatography, the purity was found to be approximately 95%, and the overall yield was 57%. When DPP was administered subcutaneously to Brattleboro rats, the potency of the anti-diuretic activity of DDAVP was enhanced to more than 250-fold. The plasma concentration of intravenously injected DDAVP in mice decreased rapidly during the first 20 min and followed by a slow elimination rate. However, in DPP administered mice, the plasma concentration actually increased in the first 20 min, followed by a slow elimination with a rate similar to that in DDAVP-injected mice. The regeneration of DDAVP was detected in the plasma of mice treated with DPP. Studies of the organ distribution in mice indicated that the liver retention of DPP was longer than that of DDAVP. On the other hand, the intestinal excretion of DPP was significantly less than that of DDAVP.

CONCLUSIONS

The 250-fold increase of the anti-diuretic potency in DPP is most likely due to a slow elimination and prolonged tissue retention, together with the regeneration of active DDAVP, in the animals. Our results indicate that reversible lipidization is a simple and effective approach for improving the efficacy of many peptide drugs.

[Investigation of the diplopia after intraocular lens implantation]

OBJECTIVE

To investigate the pathogenesis, mechanism and prognosis of diplopia after cataract extraction with intraocular lens implantation (IOL).

METHODS

Besides routine ocular examinations, refraction, ocular position, ocular movement, fusional function and image of diplopia were examined on all the patients. Forced duction was examined on partial patients.

RESULTS

Among 24 cases with diplopia after IOL implantation, there were 19 cases of binocular diplopia and 5 cases of monocular diplopia. Of the binocular diplopia, there were 17 cases of strabismic diplopia and 2 cases of diplopia due to central fusional impairment. Of the cases with monocular diplopia, there were 4 cases resulted from operative complication and one case with congenital iridocoloboma.

CONCLUSIONS

The pathogenesis of strabismic diplopia resulted from dysfunction of ocular movement is unknown. Most of the patients can obtain binocular vision by early active treatment. Monocular diplopia is partly resulted from operative complication.

Reproductive and offspring developmental effects following maternal inhalation exposure to methanol in nonhuman primates

INTRODUCTION

In an effort to improve air quality and decrease dependence on petroleum, the federal government, industry, and other groups have encouraged development of alternative fuels such as methanol to substitute for gasoline or diesel fuel. Methanol is also a candidate to provide the hydrogen for fuel cells, which are being developed for a variety of power sources (including motor vehicle engines). Before people are exposed to increased concentrations of methanol, the potential health effects of such exposures require study. Methanol, a simple alcohol containing one carbon atom, occurs naturally in plants and animals and participates in human metabolism. People regularly consume low doses of methanol in fruits, vegetables, and fermented beverages as well as soft drinks and foods sweetened with aspartame (which breaks down to methanol in the gastrointestinal tract). Despite its ubiquitous presence, methanol can be highly toxic if sufficient quantities are consumed. Ingestion of methanol (usually in the form of wood alcohol or tainted alcoholic beverages) can result in metabolic acidosis, blindness, and even death. Although the body has the capacity to metabolize the low doses of methanol to which people are regularly exposed, it cannot handle high doses because too much methanol overwhelms the body's ability to remove a toxic metabolite (formate). When formate accumulates, methanol poisoning occurs. One factor that regulates the rate at which formate is removed is the liver level of a derivative of the vitamin folic acid. People who are deficient in folic acid (including 15% to 30% of pregnant women) may be particularly susceptible to the toxic effects of methanol. If methanol were to be widely adopted as a fuel, environmental exposures would increase through ingestion of contaminated drinking water, inhalation of vapors from evaporative and other emissions, and dermal contact. Current concentrations of methanol in ambient air are very low, 1 to 30 parts per billion (ppb). If all motor vehicles in the United States were converted to 100% methanol fuel, methanol levels in ambient air are estimated to increase approximately 1,000-fold (to 1 to 10 ppm in cities) and in a worst-case situation could occasionally reach concentrations as high as 200 ppm in enclosed spaces (HEI 1987). Inhaling these concentrations of methanol for short periods of time is not predicted to affect formate production and thus should not present a health risk. However, little is known about the consequences of long-term inhalation of methanol vapors, especially in susceptible populations of pregnant women and developing fetuses. HEI, therefore, developed a research program to address this information gap.

APPROACH

Dr. Thomas Burbacher and colleagues of the University of Washington studied the effects of long-term exposure to methanol vapors on metabolism and reproduction in adult female monkeys (Macaca fascicularis) and developmental effects in their offspring, who were exposed prenatally to methanol. The investigators exposed adult female monkeys (11 to 12 animals/group) to one of four concentrations of methanol vapors (0, 200, 600, and 1,800 ppm) for 2.5 hours a day, seven days a week during the following periods: (1) before breeding, (2) during breeding, and (3) during pregnancy. They collected blood from the adults at regular intervals to monitor methanol levels (which served as a marker of internal dose) and formate concentrations. They also conducted pharmacokinetic studies to determine whether methanol disposition (which includes absorption, distribution, metabolism, and excretion) was altered as a result of repeated methanol exposures and to assess pregnancy-related changes. Because high doses of methanol damage the central nervous system, the infants (8 to 9 animals/group) were examined at regular intervals during the first nine months of life to assess their growth and neurobehavioral development.

RESULTS

Exposure to methanol vapors did n